Grant permission to user from remote or local location
GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' IDENTIFIED BY 'Password'; GRANT ALL PRIVILEGES ON *.* TO 'admin'@'69.xx.xx.20' IDENTIFIED BY 'camp1';
SET PASSWORD FOR 'root'@'localhost' = PASSWORD('Password');
UPDATE mysql.user SET Password=PASSWORD('Qua4rigadb') WHERE User='root';
SET PASSWORD FOR 'sugarcrm'@'localhost' = OLD_PASSWORD('Qua4rigadb');
HOW TO RESET THE ROOT PASSWORD
1 Stop Mysql 2 Start mysql with --skip (#mysqld --skip-grant-tables --user=root&; mysql -uroot)
3 UPDATE mysql.user SET Password=PASSWORD('Qua4rigadb') WHERE User='root'; 4 FLUSH PRIVILEGES;
To backup all the mysql # Dump all mysql databases mysqldump --add-drop-table -A --user=root --password=Qua4rigadb > /backup/mysql/databases.sql
GRANT ALL PRIVILEGES ON *.* TO 'shanker'@'localhost' IDENTIFIED BY 'shanker123' WITH GRANT OPTION;
Veritas Volume Manager is a software product from veritas Inc. and it is used to manage disk storage.
The main features of volume manager are following:
1. Allows creation of logical volumes spanning over multiple disks. This overcomes the physical limit of the disk.
2. Provides high availability storage solutions through RAID, Mirroring of disks .
3. Provides fail over features by providing transferable disk group ownership between systems.
4. Dynamic reconfiguration of disk storage in an online system state. what is veritas volume manager .
The following article describes the volume manager objects and configuration of these objects using a text menu based utility called vxdiskadm .
1.0 Volume Manager Objects
Disks
Disks are referred in volume manager by two terms - device name and disk name . The device name specifies controller , target id and slice of the disk . Disk name is the common name given to the device name as an easy to remember name .
For example device name c2t3dos2 represents controller number 2 , target id 3 , disk group 0 and slice 2 and disk01 may be its disk name . While device name is system dependent based on controller and disk id the disk name is user defined .
Disk groups :
A disk group is a collection of volume manager disks grouped together to hold the data . All the configuration changes made to a disk group are applied to the disks in that disk group only.
Volume Manager objects cannot span disk groups i.e. all the operations on a particular disk group remains confined to that particular group .
Disk groups enable high availability as these can be shared by two or more hosts but can be accessed by only one host at a time. In two hosts and a shared storage situation one host can take over the ownership of the disk groups and drives in case other host fails.
Volume Manager disks
Adding physical disks to the volume manager results in creation of public and private region in the disk by the volume manager .The public region is the disk space available for volume space and the private region stores the configuration information.
A Volume Manager disks are created from the public region of a physical disk that is under Volume Manager control. Each volume manager disk corresponds to one physical disk.
A volume manager disk is given a disk media name when it is added to a disk group which can be default or unique user defined..
Once a volume manager disk is assigned a disk media name, the disk is no longer referred to by its physical address of c#t#d#. The physical address of c#t#d# becomes known as the disk access record.
Subdisks
A subdisk is a subsection of a disk's public region and is the smallest unit of storage in Volume Manager.
A subdisk is defined by an offset and a length in sectors on a volume manager disk.
A volume manager disk can contain multiple subdisks but subdisks cannot overlap or share the same portions of a volume manager disk.
volume manager disk space that is not reserved or that is not part of a subdisk is free space. You can use free space to create new subdisks.
A subdisk is similar to a partition but with following differences :
The maximum number of partitions to a disk is eight.
There is no theoretical limit to number of subdisks that can be attached to a single plex, but it has been limited to a default value of 4096. If required, this default can be changed, using the vol_subdisk_num tunable parameter.
Plexes
A plex is a structured or ordered collection of subdisks that represents one copy of the data in a volume. A plex consists of one or more subdisks located on one or more physical disks.
A plex is also called a mirror. The terms plex and mirror can be used interchangeably, even though a plex is only one copy of the data. The terms "mirrored" or "mirroring" imply two or more copies of data.
The length of a plex is determined by the last block that can be read or written on the last subdisk in the plex.
The default naming convention for plexes in a volume is volumename-##. The default plex name consists of the volume name, a hyphen, and a two-digit number
Volumes
A volume is composed of one or more plexes not restricted by the physical size of the disk.
A volume can span across multiple disks.
Volume Manager uses the default naming convention vol## for volumes, where ## represents a two-digit number but can be user defined as per requirement.
Volume Manager Objects and Their Relationship
2.0 Volume Manager Configuration
Volume configuration consists of adding two or more disks to form disk group and create volume/s from this disk group. File system can be created on these volumes or these can be accessed as raw devices for some database applications. First step in volume manager configuration consists of adding and initializing disks under volume manager which creates a public region which is bulk of disk space available for volume space .Private region which is generally of a few megabytes stores the disk configuration information .
Most of the volume manager operation related to disks & volume can be performed by a character based menu utility call vxdiskadm
Following paragraphs describes the use of vxddiskadm to configure and manage volume manager.
#vxdiskadm
Typing vxdiskadm brings up a menu based utility (text) . The options , their explanation and screen shots are given below .Most of the options need a disk name , device name or disk group name and you can have this information by typing list in the vxdiskadm menu .The list menu option is used to display a list of disks attached to your system. This also lists removed or failed disks. Most useful to get a quick view of all disks or list details of a single disk - its name , volume association and status.
A disk needs to be formatted in order to be included in volume manager . volume manager will report unformatted disk as invalid and a will only recognize after formatting
By default all the available disks in the system are considered for inclusion as volume manager disk however to exclude certain disks, list the names of the disks to be excluded in the file /etc/vx/disks.exclude before the initialization or encapsulation. Similarly, you can exclude all disks on specific controllers from initialization or encapsulation by listing those controllers in the file /etc/vx/cntrls.exclude.
? & ?? options provide help about the menu item and menu system.
#vxdiskadm
Volume Manager Support Operations Menu: VolumeManager/Disk
1 Add or initialize one or more disks 2 Encapsulate one or more disks 3 Remove a disk 4 Remove a disk for replacement 5 Replace a failed or removed disk 6 Mirror volumes on a disk 7 Move volumes from a disk 8 Enable access to (import) a disk group 9 Remove access to (deport) a disk group 10 Enable (online) a disk device 11 Disable (offline) a disk device 12 Mark a disk as a spare for a disk group 13 Turn off the spare flag on a disk list List disk information
? Display help about menu ?? Display help about the menuing system q Exit from menus
Select an operation to perform
2.1 Add or initialize one or more disks
The formatted disks can be added or initialized with volume manager . Disk groups needs to be given for making a new group or adding disks in existing group. Default disk group is rootdg and if none is specified the disks are added to volume manager and are kept as hot spares which can be used in place of a failed disk.
Select 1 (Add or initialize one or more disks) from the vxdiskadm main menu.
Add or initialize disks Menu: VolumeManager/Disk/AddDisks
Use this operation to add one or more disks to a disk group. You can add the selected disks to an existing disk group or to a new disk group that will be created as a part of the operation. The selected disks may also be added to a disk group as spares. The selected disks may also be initialized without adding them to a disk group leaving the disks available for use as replacement disks.
More than one disk or pattern may be entered at the prompt. Here are some disk selection examples:
all: all disks c3 c4t2: all disks on both controller 3 and controller 4,target 2 c3t4d0: a single disk
Select disk devices to add: [,all,list,q,?]list
can be a single or more disks and/or controllers. If consists of multiple items, those items must be separated by white space.
list at the prompt displays a list of the disks available to the system, followed by a prompt at which you should type the device name of the disk to be added:
Select disk devices to add: [,all,list,q,?] c1t0d1
All disks attached to the system are recognized by the Volume Manager and displayed here.. Error status indicates disks not recognized by volume manager as part of volume manager and can be used to add in the volume manager .. Disks with a name , group and online status are present in volume manager in a valid volume manager disk group .One or more disks separated by space can be selected for adding into volume manager.
Here is the disk selected. Output format: [Device_Name] c1t2d0 Continue operation? [y,n,q,?] (default: y) y
You can choose to add this disk to an existing disk group, a new disk group, or leave the disk available for use by future add or replacement operations. To create a new disk group, select a disk group name that does not yet exist. To leave the disk available for future use, specify a disk group name of "none".
Which disk group [,none,list,q,?] (default: rootdg)
Use a default disk name for the disk? [y,n,q,?] (default: y)
Add disk as a spare disk for rootdg? [y,n,q,?] (default: n) n
The selected disks will be added to the disk group rootdg with default disk names.
c1t2d0
Continue with operation? [y,n,q,?] (default: y) y
The following disk device has a valid VTOC, but does not appear to have been initialized for the Volume Manager. If there is data on the disk that should NOT be destroyed you should encapsulate the existing disk partitions as volumes instead of adding the disk as a new disk. Output format: [Device_Name] c1t2d0 Encapsulate this device? [y,n,q,?] (default: y) n c1t2d0 Instead of encapsulating, initialize? [y,n,q,?] (default: n) y Initializing device c1t2d0. Adding disk device c1t2d0 to disk group rootdg with disk name disk39. Add or initialize other disks? [y,n,q,?] (default: n)
2.2 Encapsulate one or more disks
This is used to bring the disk under volume manager , which are already present in the system with data but without volume manager . Data on these disks are not disturbed and if these disks meets certain volume manager requirements these are added under volume manager.
System needs rebooting if encapsulation is used for disk with mounted filesystem or running applications . Also the old device names needs to be changed in applications/scripts to reflect the new volume name.
vfstab information is updated automatically but it is worthwhile to check vfstab if changes are proper as any discrepancy in vfstab may cause system boot failure on next reboot.
Encapsulation preserves any existing data on the disk when the disk is placed under volume manager control. To reduce the
chance of encapsulation failure, make sure that the disk meets the following requirements:-
It has a small amount of free space (at the beginning or end of the disk) that does not belong to any partition
It has two free partitions
It has an s2 slice that represents the whole disk
One of the most common application is encapsulation of root disk to bring it under volume manager and then mirror it to have an alternate boot disk .
The EEPROM variable use-nvramrc? must be set to true and an alternate boot disk alias name needs to be defined to access the second boot disk by an alternate alias name in case primary disk fails.
ok>eeprom use-nvramrc?=true
Procedure for encapsulating a disk for volume manager use is as follows:
Select menu item 2 (Encapsulate one or more disks) from the vxdiskadm main menu and follow the prompts :-
Encapsulate one or more disks Menu: VolumeManager/Disk/Encapsulate
Use this operation to convert one or more disks to use the Volume Manager. This adds the disks to a disk group and replaces existing
partitions with volumes. Disk encapsulation requires a reboot for the
changes to take effect.
More than one disk or pattern may be entered at the prompt. Here
are some disk selection examples:
all: all disks c3 c4t2: all disks on both controller 3 and controller 4, target 2 c3t4d0: a single disk
Select disk devices to encapsulate: [,all,list,q,?] c2t5d0
can be a single disk, or a series of disks and/or controllers (with optional targets). If consists of multiple items, those items must be separated by white space.
Here is the disk selected. Output format: [Device_Name] c2t5d0 Continue operation? [y,n,q,?] (default: y) y
You can choose to add this disk to an existing disk group or to a new disk group. To create a new disk group, select a disk group name that does not yet exist.
Which disk group [,list,q,?] (default: rootdg) Use a default disk name for the disk? [y,n,q,?] (default: y) The selected disks will be encapsulated and added to the rootdg disk group with default disk names.
c2t5d0
Continue with operation? [y,n,q,?] (default: y) y The following disk has been selected for encapsulation. Output format: [Device_Name]
c2t5d0
Continue with encapsulation? [y,n,q,?] (default: y) y
The disk device c2t5d0 will be encapsulated and added to the disk group rootdg with the disk name disk01. The c2t5d0 disk has been configured for encapsulation. The first stage of encapsulation has completed successfully. You should now reboot your system at the earliest possible opportunity. The encapsulation will require two or three reboots which will happen automatically after the next reboot. To reboot execute the command: shutdown -g0 -y -i6 This will update the /etc/vfstab file so that volume devices are used to mount the file systems on this disk device. You will need to update any other references such as backup scripts, databases, or manually created swap devices.
Encapsulate other disks? [y,n,q,?] (default: n) n
The disk device c2t5d0 will be encapsulated and added to the disk group rootdg with the disk name disk01. The encapsulation operation failed with the following error: It is not possible to encapsulate c2t5d0, for the following reason: Hit RETURN to continue.
Encapsulation may fail if there is not enough free space available on the disk to accommodate volume manager. If this happens, the procedure above will end abruptly with an error message as above .
2.3 Remove a disk
This option is used to remove a disk from a disk group provided there is no active volume using this disk .. If there are some volumes using the disk the those have to be either moved to some other disk or removed if they are no longer needed.
However since a diskgroup must have at least one disk you can not remove all the disks from a disk group . To remove all disks from a diskgroup you have to disable the volume group with the exception of rootdg disk group which can not be disabled .
Select menu item 3 (Remove a disk) from the vxdiskadm main menu.
Remove a disk Menu: VolumeManager/Disk/RemoveDisk
Use this operation to remove a disk from a disk group. This operation takes, as input, a disk name. This is the same name that you gave to the disk when you added the disk to the disk group.
Enter disk name [,list,q,?] disk01
Requested operation is to remove disk disk01 from group rootdg.
Continue with operation? [y,n,q,?] (default: y)
Removal of disk disk01 is complete.
Remove another disk? [y,n,q,?] (default: n)
2.4 Remove a disk for replacement
This option is used for removing the disk but retaining the name of the disk so that it can be used by the newly replaced disk . The replacement disk can be a newly added disk or already available disk in the other disk groups
Select menu item 4 (Remove a disk for replacement) from the vxdiskadm main menu.
Remove a disk for replacement Menu: VolumeManager/Disk/RemoveForReplace
Use this menu operation to remove a physical disk from a disk group, while retaining the disk name. This changes the state for the disk name to a removed disk. If there are any initialized disks that are not part of a disk group, you will be given the option of using one of these disks as a replacement.
Enter disk name [,list,q,?] disk02
Additional screens display if there are volumes associated with the disk you want to remove. You have to decide if data is needed or not needed and answer the prompts as asked .
The following devices are available as replacements: c1t1d0
You can choose one of these disks now, to replace disk02. Select "none" if you do not wish to select a replacement disk.
Choose a device, or select "none" [,none,q,?] (default: c1t1d0)
Requested operation is to remove disk disk02 from group rootdg. The removed disk will be replaced with disk device c1t1d0.
Continue with operation? [y,n,q,?] (default: y)
Removal of disk disk02 completed successfully.
Proceeding to replace disk02 with device c1t1d0.
Disk replacement completed successfully.
Remove another disk? [y,n,q,?] (default: n)
2.5 Replace a failed or removed disk
This option is used to replace a failed or removed disk . The new disk can be initialized or non initialized as this option does initialization .
Select menu item 5 (Replace a failed or removed disk) from the vxdiskadm main menu.
Replace a failed or removed disk Menu: VolumeManager/Disk/ReplaceDisk
Use this menu operation to specify a replacement disk for a disk that you removed with the "Remove a disk for replacement" menu operation, or that failed during use. You will be prompted for a disk name to replace and a disk device to use as a replacement. You can choose an uninitialized disk, in which case the disk will be initialized, or you can choose a disk that you have already initialized using the Add or initialize a disk menu operation.
Select a removed or failed disk [,list,q,?] disk02
The following devices are available as replacements: c1t0d0s2 c1t1d0s2
You can choose one of these disks to replace disk02. Choose "none" to initialize another disk to replace disk02.
Choose a device, or select "none" [,none,q,?] (default: c1t0d0s2)
The requested operation is to use the initialized device c1t0d0s2 to replace the removed or failed disk disk02 in disk group rootdg.
Continue with operation? [y,n,q,?] (default: y)
Replacement of disk disk02 in group rootdg with disk device c1t0d0s2 completed successfully.
2.6 Mirror volumes on a disk
volumes can be mirrored to another disk with available space however it can not be used to mirror existing mirrors or mirrors spanning more than one sub disk .
To mirror volumes on a disk, make sure that the target disk has an equal or greater amount of space as the originating disk and then do the following
Select menu item 6 (Mirror volumes on a disk) from the vxdiskadm main menu.
Mirror volumes on a disk Menu: VolumeManager/Disk/Mirror
This operation can be used to mirror volumes on a disk. These volumes can be mirrored onto another disk or onto any available disk space. Volumes will not be mirrored if they are already mirrored. Also, volumes that are comprised of more than one subdisk will not be mirrored.
Mirroring volumes from the boot disk will produce a disk that can be used as an alternate boot disk.
Enter disk name [,list,q,?] disk02
You can choose to mirror volumes from disk disk02 onto any available disk space, or you can choose to mirror onto a specific disk. To mirror to a specific disk, select the name of that disk. To mirror to any available disk space, select "any".
Enter destination disk [,list,q,?] (default: any) disk01
Note - Be sure to always specify the destination disk when you are creating an alternate root disk. Otherwise, the volume manager will select space available in the disk group which might span disk and will result in boot failure from this disk.
2.7 Move volumes from a disk
This option is used in case the disk is to be replaced or removed and has active volumes on the disk. . Also volumes can be moved to different disk groups for better space , performance etc.
Select menu item 7 (Move volumes from a disk) from the from the from the from the vxdiskadm main menu.
Move volumes from a disk Menu: VolumeManager/Disk/Evacuate
Use this menu operation to move any volumes that are using a disk onto other disks. Use this menu immediately prior to removing a disk, either permanently or for replacement. You can specify a list of disks to move volumes onto, or you can move the volumes to any available disk space in the same disk group.
NOTE: Simply moving volumes off of a disk, without also removing the disk, does not prevent volumes from being moved onto the disk by future operations. For example, using two consecutive move operations may move volumes from the second disk to the first.
Enter disk name [,list,q,?] disk01
You can now specify a list of disks to move onto. Specify a list of disk media names (e.g., disk01) all on one line separated by blanks. If you do not enter any disk media names, then the volumes will be moved to any available space in the disk group.
Requested operation is to move all volumes from disk disk01 in group rootdg.
NOTE: This operation can take a long time to complete.
Continue with operation? [y,n,q,?] (default: y)
Move volume vol3 ... Move volume vol3-bk00 ... Evacuation of disk disk01 is complete.
Move volumes from another disk? [y,n,q,?] (default: n)
2.8 Enable access to (import) a disk group
Used in enabling ownership of the other system to a disk group which has been deported by the other system. Used in failover configurations where the ownership of a shared disk/disk group is transferred to the other system in case of failure of current system.
Select menu item8(Enable access to (import) a disk group) from the vxdiskadmmain menu.
Enable access to (import) a disk group Menu: VolumeManager/Disk/EnableDiskGroup
Use this operation to enable access to a disk group. This can be used as the final part of moving a disk group from one system to another. The first part of moving a disk group is to use the "Remove access to (deport) a disk group" operation on the original host.
A disk group can be imported from another host that failed without first deporting the disk group. Be sure that all disks in the disk group are moved between hosts.
If two hosts share a SCSI bus, be very careful to ensure that the other host really has failed or has deported the disk group. If two active hosts import a disk group at the same time, the disk group will be corrupted and will become unusable.
Select disk group to import [,list,q,?] (default: list) newdg The import of newdg was successful.
Select another disk group? [y,n,q,?] (default: n)
2.9 Disable access to (deport) a disk group
Disk group is deported if disks groups ownership needs to be transferred to another system or all the disks in a disk groups needs to be freed from group. Disks in a disk groups to be deported should not be active.
Select menu item 9 (Remove access to (deport) a disk group) from the vxdiskadm main menu.
Remove access to (deport) a disk group Menu: VolumeManager/Disk/DeportDiskGroup
Use this menu operation to remove access to a disk group that is currently enabled (imported) by this system. Deport a disk group if you intend to move the disks in a disk group to another system. Also, deport a disk group if you want to use all of the disks remaining in a disk group for some new purpose.
You will be prompted for the name of a disk group. You will also be asked if the disks should be disabled (offlined). For removable disk devices on some systems, it is important to disable all access to the disk before removing the disk.
Enter name of disk group [,list,q,?] (default: list) newdg
The requested operation is to disable access to the removable disk group named newdg. This disk group is stored on the following disks: newdg01 on device c1t1d0s2
You can choose to disable access to (also known as "offline") these disks. This may be necessary to prevent errors if you actually remove any of the disks from the system.
Disable (offline) the indicated disks? [y,n,q,?] (default: n) Continue with operation? [y,n,q,?] (default: y)
Removal of disk group newdg was successful.
Disable another disk group? [y,n,q,?] (default: n)
2.10 Enable (online) a disk device
Disks which are turned offline by volume manager , or which are to be imported can be enabled by this option. This operation causes disks to be scanned and find out the disk belonging to a disk group.
Select menu item 10 (Enable (online) a disk device) from the vxdiskadm main menu.
Enable (online) a disk device Menu: VolumeManager/Disk/OnlineDisk
Use this operation to enable access to a disk that was disabled with the "Disable (offline) a disk device" operation.
You can also use this operation to re-scan a disk that may have been changed outside of the Volume Manager. For example, if a disk is shared between two systems, the Volume Manager running on the other system may have changed the disk. If so, you can use this operation to re-scan the disk.
NOTE: Many vxdiskadm operations re-scan disks without user intervention. This will eliminate most needs to online a disk directly, except when the disk is directly offlined.
Select a disk device to enable [,list,q,?] c1t1d0
Enable another device? [y,n,q,?] (default: n)
2.11 Disable (offline) a disk device
This option disables all access to a disk which is not part of any disk group . This is used to remove disk from volume group. Some systems do not support disks that can be removed from a system during normal operation. On such systems, the offline operation is not very useful.
Select menu item 11 (Disable (offline) a disk device) from the vxdiskadm main menu.
Disable (offline) a disk device Menu: VolumeManager/Disk/OfflineDisk
Use this menu operation to disable all access to a disk device by the Volume Manager. This operation can be applied only to disks that are not currently in a disk group. Use this operation if you intend to remove a disk from a system without rebooting.
NOTE: Many systems do not support disks that can be removed from a system during normal operation. On such systems, the offline operation is seldom useful.
Select a disk device to disable [,list,q,?] c1t1d0
Disable another device? [y,n,q,?] (default: n)
2.12 Mark a disk as a spare for a disk group
This is used to reserve the disk as an automatic replacement disk ( hot-relocation) in case of another disk in the disk group fails. Hot-relocation relocates redundant subdisks to other disks and restores the affected volume manager objects and data. If a disk has already been designated as a spare in the disk group, the subdisks from the failed disk are relocated to the spare disk. Otherwise, any suitable free space in the disk group is used.
Select menu item 12 (Mark a disk as a spare for a disk group) from the vxdiskadm main menu.
Mark a disk as a spare for a disk group Menu: VolumeManager/Disk/MarkSpareDisk
Use this operation to mark a disk as a spare for a disk group. This operation takes, as input, a disk name. This is the same name that you gave to the disk when you added the disk to the disk group.
Enter disk name [,list,q,?] disk01 Marking of disk01 in rootdg as a spare disk is complete.
Mark another disk as a spare? [y,n,q,?] (default: n)
Any VM disk in this disk group can now use this disk as a spare in the event of a failure. If a disk fails, hot-relocation should automatically occur .The failed disk needs to be replaced.
2.13 Turn off the spare flag on a disk
This is used to remove a VM Disk From the Hot-Relocation Pool & free hot-relocation spare disks for use as regular volume manager disks While a disk is designated as a spare, the space on that disk is not used as free space for the creation of volume manager objects within its disk group and this option makes this space available.
Select menu item 13 (Turn off the spare flag on a disk) from the vxdiskadm main menu.
Turn off the spare flag on a disk Menu: VolumeManager/Disk/UnmarkSpareDisk
Use this operation to turn off the spare flag on a disk. This operation takes, as input, a disk name. This is the same name that you gave to the disk when you added the disk to the disk group.
Enter disk name [,list,q,?] disk01
Disk disk01 in rootdg no longer marked as a spare disk.
Turn-off spare flag on another disk? [y,n,q,?] (default: n)
After using the vxdiskadm for configuring disks and diskgroups next step is to configure volumes and then use them for storage operations . The second part of this article discusses this aspect of volume manager .
The vxassist utility in Veritas Volume Manager is used to create volumes, add mirrors and logs to existing volumes, extend and shrink existing volumes, provides for the migration of data from a specified set of disks, and provides facilities for the on-line backup of existing volumes.
The default behavior of vxassist is to create volumes in the rootdg diskgroup if diskgroup is not specified . The default length is taken as number of blocks but this can be specified in Kilobytes or Megabytes or Gigabytes.
vxassist command syntax :
vxassist
Commonly used options are given below (See man vxassist for complete list of supported options)
-g for specifying diskgroups
-b for background operation
-d file containing defaults for vxassist if not specified /etc/default/vxassist is used
Keywords used are make , mirror , move , growto ,growby ,shrintto ,shirnkby ,snapstart , snapshot ,snapwait
Attributes specify volumes layout disks controllar to include exclude etc
Raw Device Node /dev/vx/rdsk/diskgroup_name/volume_name
_______________________________________
1. Creating a Volume :
1.1 Creating a Concatenated Volume
By default, vxassist creates a concatenated volume using the space available on a disk or on the number of disks in a diskgroup if the volume size specified is more then the one available on a single disk.
Disks can be specified from a diskgroup for a volume group but if not mentioned available disks are selected by the volume manager.
Command syntax :
vxassist make volume_name volume_length
To create a new volume appvol of 100 MB in the default disk group rootdg with available disks:
#vxassist make appvol 100m
To create the volume appvol of 100MB on disk03
#vxassist make appvol 100m disk03
1.2 Creating a Striped Volume
A striped volume contains at least one plex that consists of two or more subdisks located on two or more physical disks.
Command Syntax :
vxassist make volume_name length layout=stripe
To create a striped volume appvol2 with the default stripe unit size on the default number of disks
#vxassist make appvol2 100m layout=stripe
To create a striped volume appvol2 100MB striped volume on three specific disks.
#vxassist make appvol2 100m layout=stripe disk04 disk05 disk06
1.3 Creating a RAID-5 Volume
A RAID-5 volume contains a RAID-5 plex that consists of two or more subdisks located on two or more physical disks. Only one RAID-5 plex can exist per volume. A RAID-5 volume may also contain one or more RAID-5 log plexes, which are used to log information about data and parity being written to the volume.
Command Syntax :
vxassist make volume_name length layout=raid5
To create the RAID-5 volume appvol4 with the default stripe unit size on the default number of disks with RAID-5 log,
#vxassist make appvol4 100m layout=raid5.
2. Extending a Volume
Caution : If you plan to use volume size change (grow or shrink ) on a volume with data make sure you have the good backup of the volume available before carrying out such operation .
2.1 Extending a volume up to certain length,
Command syntax
vxassist growto volume_name length
To extend vol3 upto 8000 sectors, type:
#vxassist growto vol3 8000
2.2 Extending by a Given Length
Command Syntax
vxassist growby volume_name length
To extend volapp by 1000 sectors, type:
#vxassist growby volapp 1000
3. Shrinking a Volume
Caution - Do not shrink a volume below the size of the file system. If you have a VxFS file system, you can shrink the file system and then shrink the volume. If you do not shrink the file system first, you risk unrecoverable data loss.
Always make sure you have a good backup of the data volume to be shirnked.
3.1 Shrinking to a Given Length
Shrink a volume to a specific length as follows:
vxassist shrinkto volume_name length
Make sure you do not shrink the volume below the current size of the file system or database using the volume. This command can be safely used on empty volumes.
To shrink volcat to 1300 sectors, type:
#vxassist shrinkto volcat 1300
3.2 Shrinking by a Given Length
Shrink a volume by a specific length as follows:
vxassist shrinkby volume_name length
To shrink volcat by 8000 sectors, type:
#vxassist shrinkby volapp2 8000
4. Removing a Volume
Removing a volume requires removing all references to the volumes to be removed like unmounting the volume if mounted and removing its reference from /etc/vfstab .
An active volume has to be stopped first to stop all the activities to the volume only then it can be removed
Stopping Volume :
Command Syntax
vxvol stop volume_name
To stop appvol1
#vxvol stop appvol1
Removing Volume
Command Syntax
vxedit -rf rm volume_name
To remove the volume appvol1
#vxedit -rf rm appvol11
5. Mirroring a Volume
Mirroring allow data to be written simultaneously to two disks so that in case of failure of one disk data is available from the other mirrored disk. Boot disks can be mirriored to provide alternate booting disk .
5.1 Creating & Mirroring a New Volume
Command Syntax :
vxassist make volume_name length layout=mirror
To create the mirrored volume, appvol22 of 100mb
#vxassist make appvol22 100m layout=mirror
To create a volume with Dirty Region Logging enabled
#vxassist make volume_name length layout=mirror,log
5.2 Mirroring an Existing Volume
Command syntax
vxassist mirror volume_name
Creating a mirror of volume vol44:
#vxassist mirror vol44
5.3 Mirroring All Volumes
To mirror all existing volumes to available disk space
/etc/vx/bin/vxmirror -a
6. Removing a Mirror
Removing a mirror involves first dissociating the plex from its volume and then removing the plex and any associated subdisks completely.The last valid mirror plex associated with a volume cannot be removed.
Dissociate and remove the plex from its volume as follows:
vxplex -o rm dis plex_name
vxprint -h shows the volume and associated plexes :
Disk group: rootdg TY NAME ASSOC KSTATE LENGTH PLOFFS STATE TUTIL0 PUTIL0 v volm fsgen ENABLED 10240 - ACTIVE - - pl volm-01 volm ENABLED 10240 - ACTIVE - - sd disk01-02 volm-01 - 10240 0 - - - pl volm-02 volm ENABLED 10240 - ACTIVE - - sd disk02-03 volm-02 - 10240 0 - - -
To disassociate and remove volmir-02 from volmir, type:
#vxplex -o rm dis volm-02
The output of vxprint -h for volm now shows volume volm with only one plex::
Disk group: rootdg TY NAME ASSOC KSTATE LENGTH PLOFFS STATE TUTIL0 PUTIL0 v volm fsgen ENABLED 10240 - ACTIVE - - pl volm-01 volmir ENABLED 10240 - ACTIVE - - sd disk01-02 volmir-01 - 10240 0 - - -
7. Adding a RAID-5 Log
A RAID-5 log maintains a copy of the data and parity being written to the volume at any given time. If a system failure occurs, VxVM can replay the RAID-5 log to resynchronize the volume. This copies the data and parity that was being written at the time of failure from the log to the appropriate areas of the RAID-5 volume.
RAID-5 log plexes are used to log information about data and parity being written to the raid volume. A log plex is created for the volume by default when a raid volume is created but additional ones can be added by following command .
vxassist addlog name_of_raid5_vol
8. Adding a DRL Log
Dirty region logging (DRL) is used with mirrored volume layouts. DRL keeps track of the regions that have changed due to I/O writes to a mirrored volume. Prior to every write, a bitmap is written to a log to record the area of the disk that is being changed. In case of system failure, DRL uses this information to recover only the portions of the volume that need to be recovered.
To put Dirty Region Logging into effect for a volume, a log subdisk must be added to that volume and the volume must be mirrored. Only one log subdisk can exist per plex.
The following example creates a log for the mirrored volume vol03:
#vxassist addlog vol03
When vxassist is used to add a log subdisk to a volume, a log plex is also created to contain the log subdisk, by default.
Once created, the plex containing a log subdisk can be treated as a regular plex. Data subdisks can be added to the log plex. The log plex and log subdisk can be removed using the same procedures used to remove ordinary plexes and subdisks.
9. Removing a RAID-5 Log
Removing a RAID-5 log involves first dissociating the log from its volume and then removing the log and any associated subdisks completely.
Dissociate the log from its volume as follows:
#vxplex -o rm dis plex_name
To identify the log plex, use the command:
vxprint -ht raid5_volume_name
To disassociate the log plex volrd-02 from volrd, type:
#vxplex -o rm dis volrd-02
The output of vxprint -h for volrd now shows:
Disk group: rootdg TY NAME ASSOC KSTATE LENGTH PLOFFS STATE TUTIL0 PUTIL0 v volrd raid5 ENABLED 32 - ACTIVE - - pl volrd-01 volrd ENABLED 32 - ACTIVE - - sd disk01-02 volrd-01 - 32 0 - - - sd disk02-03 volrd-01 - 32 0 - - -
10. Preparing a Volume for Online Backup
Volume manager provides an easy way to take backup of the online data by creating an offline snapshot mirror of the volume .
The vxassist snapstart operation creates a write-only backup mirror, which is attached to and synchronized with the volume to be backed up and later detached and made offline by vxassist snapshot command . The snapshot volume can be used by backup utilities while the original volume continues to be available for applications and users.
The volume backup method described here does not apply to RAID-5 volumes.
Backing up a volume with vxassist involves the following procedure
Create a snapshot mirror
snapstart starts creating a online snapshot mirror of the volume using the available disk space . The snapshot is completed with vxassist snapshot command when offline snapshot volume is created with a userdefined name .
Command Syntax:
vxassist snapstart volume_name
To create a snapshot mirror of a volume called vol8, type
#vxassist snapstart vol8
Create a snapshot volume
Command Syntax
vxassist snapshot volume_name new_volume_name
To create a snapshot volume of vol8, type:
#vxassist snapshot vol8 snapvol8
You can now back up the snapshot volume by whatever means you prefer. To avoid wasting space, you can then remove the snapshot volume, which occupies as much space as the original volume
11 Displaying Volume Configuration Information
The vxprint command can be used to display information about how a volume is configured.
Display the volume, mirror, and subdisk record information for all volumes as follows:
#vxprint -ht
Disk group: rootdg
DG NAME NCONFIG NLOG MINORS GROUP-ID
DM NAME DEVICE TYPE PRIVLEN PUBLEN STATE
V NAME USETYPE KSTATE STATE LENGTH READPOL PREFPLEX
PL NAME VOLUME KSTATE STATE LENGTH LAYOUT NCOL/WID MODE
SD NAME PLEX DISK DISKOFFS LENGTH [COL/]OFF DEVICE MODE
dg rootdg 759096729.1025.tweety
dm disk10 c1t0d0s2 sliced 559 1044400 -
dm disk20 c2t0d0s2 sliced 559 1044400 -
v pubs fsgen ENABLED ACTIVE 2288 SELECT -
pl pubs-01 pubs ENABLED ACTIVE 2288 CONCAT - RW
sd disk10-01 pubs-01 disk10 0 2288 0 c0t0d0 ENA
v vol8 fsgen ENABLED ACTIVE 20480 SELECT -
pl vol8-01 vol8 ENABLED ACTIVE 20480 CONCAT - RW
sd disk10-02 vol8-0 disk10 2288 20480 0 c0t1d0 ENA
where dg is a disk group, dm is a disk, v is a volume, pl is a plex, and sd is a subdisk. The top few lines indicate the headers that match each type of output line that follows. Each volume is listed along with its associated plex(es) and subdisk(s).
Display volume-related information for a specific volume as follows:
