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Update the LVM section with raid5 specific tip to reduce Setup time
Signed-off-by: Anthony Floeder <anthony.floeder@hpe.com>
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README.md

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Press Ctrl+C to quit.
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CStopping server...
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```
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docs/guides/storage-profiles/readme.md

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@@ -10,7 +10,7 @@ Storage Profiles allow for customization of the Rabbit storage provisioning proc
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1. The RAID type used for storage
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2. Any mkfs or LVM args used
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3. An external MGS NID for Lustre
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4. A boolean value indicating the Lustre MGT and MDT should be combined on the same target device
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4. A boolean value indicating the Lustre MGT and MDT should be combined on the same target device
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DW directives that allocate storage on Rabbit nodes allow a `profile` parameter to be specified to control how the storage is configured. NNF software provides a set of canned profiles to choose from, and the administrator may create more profiles.
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#### LVM
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A RAID logical volume can be used with XFS and Raw allocations.
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NOTE: gfs2 allocations cannot use RAID logical volumes because the LV is shared.
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A RAID logical volume can be used with XFS and Raw allocations.
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To create a redundant LV, `--type raid[x]` and `--nosync` should be specified in the `lvcreate` command. Also, the `--stripes` parameter should be adjusted accordingly to specify the number of data stripes. For `raid5`, `$DEVICE_NUM-1` is used.
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> **Note:** GFS2 allocations cannot use RAID logical volumes because the LV is shared between multiple nodes.
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To create a redundant LV, specify `--type raid[x]`, `--activate y`, and `--nosync` in the `lvcreate` command. The `--nosync` option allows the RAID volume to be used immediately without waiting for initial synchronization.
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> **Note:** In the `raid5` case when **both** `--activate y` and `--nosync` are specified, the initial sync operation is skipped which reduces the time to ready significantly.
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The `--stripes` parameter should be adjusted according to the RAID type:
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- **RAID0**: `--stripes $DEVICE_NUM` (all devices are data stripes)
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- **RAID1**: `--stripes 1` (mirrored, only one data stripe)
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- **RAID5**: `--stripes $DEVICE_NUM-1` (one device for parity)
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- **RAID6**: `--stripes $DEVICE_NUM-2` (two devices for parity)
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To allow the LV to rebuild after a drive is replaced, `vgExtend`, `lvRepair`, and `vgReduce` should be specified in the `lvmRebuild` section.
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vgExtend: $VG_NAME $DEVICE
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vgReduce: --removemissing $VG_NAME
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lvRepair: $VG_NAME/$LV_NAME
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lvCreate: --activate n --zero n --nosync --type raid5 --extents $PERCENT_VG --stripes $DEVICE_NUM-1
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--stripesize=32KiB --name $LV_NAME $VG_NAME
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lvCreate: |
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--activate y --zero n --nosync --type raid5 --extents $PERCENT_VG
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--stripes $DEVICE_NUM-1 --stripesize=32KiB --name $LV_NAME $VG_NAME
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lvRemove: $VG_NAME/$LV_NAME
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mkfs: $DEVICE
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mountCompute: $DEVICE $MOUNT_PATH
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lockStop: --lock-stop $VG_NAME
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vgCreate: --shared --addtag $JOBID $VG_NAME $DEVICE_LIST
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vgRemove: $VG_NAME
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```
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## Command Line Variables
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### global
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### Global
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- `$JOBID` - expands to the Job ID from the Workflow
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- `$USERID` - expands to the User ID of the user who submitted the job
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- `$GROUPID` - expands to the Group ID of the user who submitted the job
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### NnfSystemStorage specific
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- `$COMPUTE_HOSTNAME` - Expands to the hostname of the compute node that will use the allocation. This can be used to add a tag during the lvcreate
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```
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```sh
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lvCreate --zero n --activate n --extents $PERCENT_VG --addtag $COMPUTE_HOSTNAME ...
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```
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```

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