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Frequently Asked Questions - SnapProtect for UNIX File System

Table of Contents

General

What provisioning policies can I use?

Provisioning Policies are optional to use. During the creation of the secondary snapshot copy, the following Provisioning Policies are automatically created and available for selection in the CommCell Console:

  • SnapProtect_RAID-DP
  • SnapProtect_Dedupe
  • SnapProtect_Mirror_Destination

If you need to create your own provisioning policy, ensure it is defined with the following naming convention in the OCUM server:

SnapProtect_<provisioning_policy_name>

where "SnapProtect_" is the prefix required for the provisioning policy to be available in the SnapProtect software.

What happens when a vault/mirror copy is created?

During an Auxiliary Copy job, a new dataset is created or an existing dataset is modified with new data members, as explained in the following flow of events:

  1. When the SnapProtect software assigns data to the service catalogue, a new baseline transfer may have started in the OnCommand Unified Manager (OCUM) server.
  2. The Auxiliary Copy job details display its status as the baseline transfer is in progress.
  3. Once the baseline transfer is completed, the SnapProtect software adds the snaps to the backup list, and the backup starts with the OCUM.
  4. If SnapMirror is the destination copy, then the SnapProtect software sends a command to update the mirror.

    The OCUM job is monitored and marked as completed/failed depending on the OCUM job status.

How are snapshots copied during a backup copy operation?

The snapshots are copied to media in a sequential order. If you wish to perform an inline backup copy operation and a previously selected snapshot has not been copied to media, the current SnapProtect backup job will complete without creating the backup copy and you will need to create an offline backup copy for the current backup.

How can I back up and restore all virtual machines in a specific datastore?

All virtual machines in a specific datastore can be backed up and restored together as follows:

  1. Create a new subclient that will be dedicated to the datastore containing the virtual machines you want to back up. Consider giving this subclient the name of the datastore you are backing up for easy identification in the CommCell Console. For more information, see Adding Subclient Content.
  2. Schedule routine backups of the subclient as described in Scheduling a Backup.
  3. When a restore is needed, you can restore all virtual machines within the datastore by performing a browse operation on the subclient, selecting all virtual machines displayed in the Browse window, and selecting either the original datastore or a new datastore as the destination from the Restore Options dialog box.

    For steps to restore a VM in place or out of place, see Restoring Full Virtual Machines.

You can also customize backups and restores for other entities, such as ESX servers or resource pools.

What should I take into account when using retention by number of jobs?

Configuring a storage policy or snapshot copy with job based retention is recommended for File System and File System like Agents, and not for Database Agents.

Review the following scenarios if you are using the retention by number of jobs configuration:

  • During a browse operation, deleted files may be displayed for recovery. If the jobs containing these files are pruned by the retention criteria, the deleted files will be irrecoverable.
  • You may need to manually delete jobs from deconfigured clients. These clients will continue to retain the old jobs since new jobs will not run again on them.
  • When you associate a new storage policy to a subclient, it is important to perform a full backup operation in order to be retained by the new storage policy. The old storage policy will continue to retain the old jobs until you manually delete them.

What UTF Setting should be used for volume language?

To successfully browse and restore files on a NetApp filer that contain Unicode characters, it is recommended to use the UTF-8 setting for volume language. Please consult with NetApp for implications of changing volume language.

How is the OnCommand Unified Manager server affected when a snap copy is deleted?

If you delete a snapshot copy, the following components in the OnCommand Unified Manager server will be affected:

  • The storage services associated to the snapshot copy will be deleted.
  • Datasets associated with the deleted storage service will be deleted.

    Secondary volumes/datasets are not deleted as they are stored in case you need to perform a restore operation from a deleted dataset. Secondary datasets can be removed manually, if needed.

  • Any relationship associated with a dataset will be deleted within a configurable period of time defined in the OnCommand Unified Manager server.
  • Base snapshot copies remain available.

Is multi instancing supported?

No. Multi Instancing is not supported for SnapProtect backup.

Can I use Media Explorer to restore data?

No. You cannot use Media Explorer to restore data. However, you can use the Media Explorer to restore SnapProtect backup data from the backup copy.

How do I determine the number of streams to be used for a restore operation from an SnapProtect backup?

For DB2, SAP for Oracle, and Oracle iDataAgents, when restoring from a snapshot using file system, the number of streams depends on the number of mount points used for the restore operation. Similarly, when restoring from a backup copy using file system, the number of streams depends on the number of media groups used for the restore operation.

Can I back up physical RDMs in a virtual machine using SnapProtect?

Yes. SnapProtect backups of Raw Device Map (RDM) disks (passthrough disks for Hyper-V) are supported for File System agents configured in a virtual machine in physical compatibility mode. For a detailed list of restrictions, see SnapProtect Backup - Support.

What are the commands used for device discovery?

During an SnapProtect backup job, the SnapProtect software runs a set of commands to discover storage devices.

The following table displays the commands that are used to list, rescan and delete adapters/devices for each operating system:

Operating System List FIBRE CHANNEL ADAPTERS Rescan FIBRE CHANNEL ADAPTERS Rescan ISCSI Devices Delete Device

AIX

<Base>/scan_fc_adapters.sh cfgmgr -l <hba_name> cfgmgr -l <iscsi_adapter> rmdev -d -l <hdisk_name>

HP-UX

<Base>/scan_fc_adapters.sh
  1. Obtain the path for the host bus adapter (HBA):

    ioscan -unfC fc

  2. Scan the HBA path

    ioscan -H <HBA_path>

  For Legacy HP-UX (earlier than 11.23):

rmsf –a <device>

For non-Legacy HP-UX:

  1. Obtain persistent name mapping:

    ioscan –m dsf

  2. Check device availability:

    ioscan –kNF devname<device>

  3. Delete the device:

    rmsf –H <device>

Linux

<Base>/scan_fc_adapters.sh
  1. Perform the hardware loop initialization (LIP):

    echo 1 > /sys/class/fc_host/<$host>/issue_lip

  2. Perform a SCSI mid-level rescan:

    echo '---' > /sys/class/fc_host/<$host>/scan

  • For Red Hat 4 computers:

    /sbin/iscsi -rescan

  • For SuSE Linux 9 computers:

    /etc/init.d/iscsi reload /bin/rescan-scsi-bus.sh -r –L 512 –w –c --nooptscan

  • For SuSE Linux 10 and Red Hat 5 computers:

    /sbin/iscsiadm -m session -R

echo 1 > /sys/block/<device>/device/delete

Solaris

<Base>/scan_fc_adapters.sh cfgadm -c configure <controller> devfsadm -i iscsi devfsadm -C -c disk

Can I create my own commands to perform device discovery?

Yes, you can customize the device deletion and the rescan logic by creating the following additional settings:

Key Description
DeleteDevice This key will trigger a custom script which will perform an OS level device deletion. Once all the devices are removed, the SnapProtect software will remove the LUNs from the storage arrays.

Use this key if you need to unmount snapshots that are mapped to either the proxy or source machine. The key will delete all devices mapped to the machine.

To add or edit an additional setting, follow the steps in Add or Modify an Additional Setting.

Use these arguments:

  • In the Name box, type DeleteDevice. The Category and Type details will be automatically displayed.
  • In the Value box, type the full path to the script. The device name will be passed as an argument.
RefreshBUS This key will trigger a custom script for each host bus adapter that needs to be rescanned.

Use this key if you need to rescan the machine for any new devices each time a snapshot is mounted or unmounted.

To add or edit an additional setting, follow the steps in Add or Modify an Additional Setting.

Use these arguments:

  • In the Name box, type RefreshBUS. The Category and Type details will be automatically displayed.
  • In the Value box, type the full path to the script. The WWPN of the adapter will be passed as an argument.

After creating the above additional settings, you can use the following script examples:

On Linux Computers

#-------------------------------------------------------------#Example 1: Linux Rescan Script to be used by RefreshBUS key
#-------------------------------------------------------------#!/bin/sh
hba_wwpn=$1
#This line sets $Fc_adapter. (See o/p of scan_fc_adapters.sh) eval `/opt/software/Base/scan_fc_adapters.sh | grep $hba_wwpn | awk '{print $1}'`
#Add your own custom commands here.
#Perform scsi midlevel rescan. (May not be needed if you have #your custom scan command above ).
echo '- - -' > /sys/class/scsi_host/${Fc_adapter}/scan
exit 0
#-------------------------------------------------------------#Example 2: Linux Device Deletion Script to be used by #DeleteDevice key
#-------------------------------------------------------------#!/bin/sh
device=$1
#Add your own custom commands here.
#The one below is what SnapProtect uses.
echo 1 > /sys/block/$device/device/delete
exit 0

On AIX Computers

#-------------------------------------------------------------#Example 1: AIX Rescan Script to be used by RefreshBUS key
#-------------------------------------------------------------#!/bin/sh
hba_wwpn=$1
#This line sets $Fc_adapter. (See o/p of scan_fc_adapters.sh) eval `/opt/software/Base/scan_fc_adapters.sh | grep $hba_wwpn | awk '{print $1}'`
#Add your own custom commands here.
#Perform scan using cfgmgr ( May not be needed if you have #your custom scan command above ).
cfgmgr –l $Fc_adapter
exit 0
#-------------------------------------------------------------#Example 2: AIX Device Deletion Script to be used by #DeleteDevice key
#-------------------------------------------------------------#!/bin/sh
device=$1
#Add your own custom commands here.
#The one below is what SnapProtect uses.
rmdev –d –l $device
exit 0

How does SnapProtect select target devices during clone/snap operations?

When you configure an storage device using Array Management in the CommCell Console, the Device Group text box defines the target device group where SnapProtect will move the source and target devices during SnapProtect backup operations. This option does not specify the source device group (from where a device should be found during Snap/Clone operations).

The following table explains the default behavior for selecting a Snap or Clone target device:

Scenarios based on Array Management Options Target device is selected from... Source and Target devices are moved to...
Device Group is not specified and Use devices only from this device group is not checked Any device in the array CV_PROTECTION_GROUP device group
Device Group is not specified but Use devices only from this device group is checked CV_PROTECTION_GROUP device group CV_PROTECTION_GROUP device group
Device Group is specified but Use devices only from this device group is not checked Any device in the array The device group specified in Device Group
Device Group is specified and Use devices only from this device group is checked The device group specified in Device Group The device group specified in Device Group

Can I include root folder (/) as subclient content for SnapProtect?

No, root folder (/) should not be included as subclient content for SnapProtect.

What non-native FC drivers are supported?

QLogic SANSurfer CLI on SuSE Linux Enterprise Server 10 SP2.

Can I perform a cross platform restore of ACLs?

No, the restore of ACLs from one operating system to another is not supported.

Can I restore ACLs from one file system type to another?

The restore of ACLs from one file system type to another may fail as the ACLs restore is dependent on the file system implementation. For example, ACLs which are backed up from ext3 cannot be restored to NFS and vice versa. Also, if you attempt to restore data from one file system type to another with ACLs included, but the file system is mounted without ACLs, the restore operation will fail. To workaround this issue ensure that the file system is mounted with ACLs before attempting a restore operation.

To prevent the restore operation from failing you can restore data without the ACLs included.

Hardware reverts for AIX logical volumes. What happens during this operation?

When you revert all the logical volumes in the AIX Logical Volume Manager, the revert operation supports all logical volume types and all their attributes are preserved. However, for revert operations on single logical volumes, striped volumes are not supported.

The following table displays the logical volume attributes that are preserved when you revert a single volume:

Attribute Name Description

inter

Inter-physical volume allocation policy

intra

Intra-physical volume allocation policy

label

Volume label

Relocatable

Defines if relocation is allowed during reorganization of the logical volume

strictness

Strict allocation policy

type

Logical volume type

upperbound

Upper-bound on the physical volume used for new allocations

permission

Access permission of the logical volume

mirror write consistency

Defines if mirrored copies are in a consistent/active state

serialize IO

Defines if logical volumes are overlapping I/O serialized

sched policy

Defines which scheduling policy is being used when more that one logical partition is written

BB policy

Bad block relocation policy

write verify

Defines if all verified write operations are followed by a follow up read operation

Is the softlink path supported for this iDataAgent?

No. Softlinks are not supported for this iDataAgent's datafile paths and archive log location. you should use the real paths.

You can create alias device using mknod for raw devices.