Parameters for the create snapshotVirtualDiskcommand enable you to define the snapshot virtual disk to suit the requirements of your storage array. Table 4-2 lists the parameters and descriptions of what the parameters do. Table 4-2. Snapshot Virtual Disk Parameters
Parameter Description
physicalDiskType Specifies the type of physical disk to use for the snapshot repository virtual disk. The choice is either Serial Attached SCSI (SAS) or Serial Advanced Technology Attachment (SATA). This parameter works only with the count-based repository method of defining a snapshot virtual disk.
repositoryDiskGroup Specifies the disk group in which to build the snapshot virtual disk. Default builds the snapshot repository virtual disk in the same disk group as the source virtual disk.
freeCapacityArea Specifies the amount of storage space to use for the snapshot repository virtual disk. Free storage space is defined in units of bytes, kilobytes, megabytes, or gigabytes.
userLabel Specifies the name to give to the snapshot virtual disk. If you do not choose a name for the snapshot virtual disk, the RAID controller modules create a default name using the source virtual disk name. For example, if the source virtual disk name is Mars_Spirit_4 and it does not have a snapshot virtual disk, the default snapshot virtual disk name is Mars_Spirit_4-1. If the source virtual disk already has n– 1 number of snapshot virtual disks, the default name is Mars_Spirit_4-n.
The following example of the create snapshotVirtualDisk command includes user-defined parameters: client>smcli 123.45.67.89 -c "create snapshotVirtualDisk sourceVirtualDisk= \"Mars_Spirit_4\" repositoryRAIDLevel=5 repositoryPhysicalDiskCount=5 physicalDiskType= SAS userLabel=\"Mars_Spirit_4_snap1\"
repositoryUserLabel Specifies the name to give to the snapshot repository virtual disk. If you do not choose a name for the snapshot repository virtual disk, the RAID controller modules create a default name using the source virtual disk name. For example, if the source virtual disk name is Mars_Spirit_4 and it does not have an associated snapshot repository virtual disk, the default snapshot repository virtual disk name is Mars_Spirit_4-R1. If the source virtual disk already has n– 1 number of snapshot repository virtual disks, the default name is
Mars_Spirit_4-Rn.
warningThresholdPercent Specifies how full to allow the snapshot repository virtual disk to get before sending a warning that the snapshot repository virtual disk is close to capacity. The warning value is a percentage of the total capacity of the snapshot repository virtual disk. The default value is 50, which represents 50 percent of total capacity. (Change this value using the set snapshotVirtualDisk
command.)
repositoryPercentOfSource Specifies the size of the snapshot repository virtual disk as a percentage of the source virtual disk size. The default value is 20, which represents 20 percent of the source virtual disk size.
repositoryFullPolicy Specifies how snapshot processing continues if the snapshot repository virtual disk is full. You can choose to fail writes to the source virtual disk (failSourceWrites) or fail writes to the snapshot virtual disk
(failSnapShot). The default value is failSnapShot. Table 4-2. Snapshot Virtual Disk Parameters (continued)
repositoryUserLabel=\"Mars_Spirit_4_rep1\" warningThresholdPercent=75
repositoryPercentOfSource=40
repositoryFullPolicy=failSnapShot;"
The following example is the script file version of the command: create snapshotVirtualDisk sourceVirtualDisk= "Mars_Spirit_4" repositoryRAIDLevel=5 repositoryPhysicalDiskCount=5 physicalDiskType= SAS userLabel="Mars_Spirit_4_snap1" repositoryUserLabel="Mars_Spirit_4_rep1" warningThresholdPercent=75 repositoryPercentOfSource=40 repositoryFullPolicy=failSnapShot;
NOTE: In the previous examples, the names for the snapshot virtual disk and repository virtual disk are defined by the user. If you do not choose to create names for the snapshot virtual disks or the repository virtual disks, the RAID controller modules provide default names. (See "Names of Snapshot Virtual Disks and Repository Virtual Disks" on page 72 for an explanation of naming conventions.)
Names of Snapshot Virtual Disks and Repository Virtual Disks
The names of snapshot virtual disks and repository virtual disks can be any combination of alphanumeric characters, hyphens, and underscores. The maximum length of the virtual disk names is 30 characters. You must enclose the name in quotation marks. The character string cannot contain a new line. Make sure that you use unique names or the RAID controller module firmware returns an error.
One technique for naming the snapshot virtual disk and the repository virtual disk is to add a hyphenated suffix to the original name of the source virtual disk. The suffix distinguishes between the snapshot virtual disk and the repository virtual disk. For example, if you have a source virtual disk with a name Engineering Data, the snapshot virtual disk can have a name Engineering Data-S1. The repository virtual disk can have a name of Engineering Data-R1.
If you do not choose a unique name for the either the snapshot virtual disk or repository virtual disk, the RAID controller modules create a default name by using the name of the source virtual disk. For example, if the name of the source virtual disk is aaa and it does not have a snapshot virtual disk, then the
default name is aaa-1. If the source virtual disk already has n– 1 number of snapshot virtual disks, then the default name is aaa-n. Similarly, if the name of the source virtual disk is aaa and it does not have a repository virtual disk, then the default repository virtual disk name is aaa-R1. If the source virtual disk already has n –1 number of repository virtual disks, then the default name is aaa-Rn.
In the examples from the previous section, the user-defined name of the snapshot virtual disk was Mars_Spirit_4_snap1. The user-defined name of the repository virtual disk was Mars_Spirit_4_rep1. The default name provided by the RAID controller module for the snapshot virtual disk would be Mars_Spirit_4-1. The default name provided by the RAID controller module for the repository virtual disk would be Mars_Spirit_4-R1.
Changing Snapshot Virtual Disk Settings
The set (snapshot) virtualDisk command enables you to change the property settings for a snapshot virtual disk. Using this command, you can change the following parameters:
• Name of the snapshot virtual disk • Warning threshold percent • Repository full policy
The following example shows the command to change the name of a snapshot virtual disk:
client>smcli 123.45.67.89 -c "set virtualDisk [\"Mars_Spirit_4-1\"] userLabel=\"Mars_Odyssey_3- 2\";"
The following example is the script file version of the command: set virtualDisk ["Mars_Spirit_4-1"] userLabel= "Mars_Odyssey_3-2";
When you change the warning threshold percent and repository full policy, you can apply the changes to one or several snapshot virtual disks. The following example uses the set (snapshot) virtualDisk command to change these properties on more than one snapshot virtual disk:
client>smcli 123.45.67.89 -c "set virtualDisks [\"Mars_Spirit_4-1\" \"Mars_Spirit_4-2\"
\"Mars_Spirit_4-3\"] warningThresholdPercent=50 repositoryFullPolicy=failSourceWrites;"
The following example is the script file version of the command: set virtualDisks ["Mars_Spirit_4-1" "Mars_Spirit_4-2" "Mars_Spirit_4-3"]
warningThresholdPercent=50 repositoryFullPolicy= failSourceWrites;