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LVM, EVA, and DLE, and any other TLA you can think of!

 
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EU-Admins-UNIX
Regular Advisor

LVM, EVA, and DLE, and any other TLA you can think of!

Hi

 

We have two systems, A & B.  Both are running 11v3.

A is Prod, B is Pre-Prod.

 

On a week-nightly basis, snap clones are created of some of A's LUNS using SSSU scripts.  These snaps are then presented and mounted on B.

 

The following night, these snaps are unomunted from B, deleted, re-created, and re-mounted.

 

The scripts we use maintain the same LUN ID, VG names, WWN's etc.

 

I am required to increase the size of one of the LUNs on both systems from 400GB to 500GB.  Last week, I resized the SNAP LUN on B on the EVA, and tried to run some vgmodify commands, but couldn't.  Now looking at the SNAP LUN again, it has gone back fdown to 400GB.

 

My question is, could someone please explain the steps needed to make this happen with ZERO downtime.

 

If any file contents, scripts contents are required, let me know.

 

Best Regards

 

Tariq

6 REPLIES 6
Highlighted
Khairy
Esteemed Contributor

Re: LVM, EVA, and DLE, and any other TLA you can think of!

hi,

do share us the script. we need to understand on how many LUNs are involve.

Generally, there are 2 option i could see from here:

option A:
(1) create new LUN, present to server A, vgextend,lvextend,fsadm (increase filessytem online)
(2) modify your script to snap the old and new LUN and present it to server B
(3) From server B, the script should vgimport the existing LUN and new snap LUN and mount them.

Option B:
(1) in server A, increase the LUN size, ioscan, vgmodify (to take up the new lun size),lvextend,fsadm.

with this approach, there will be not much thing need to do in the script as the script will create a snap on existing LUN. If the new LUN is 500GB, a new 500GB snap will be created.

//
Highlighted
EU-Admins-UNIX
Regular Advisor

Re: LVM, EVA, and DLE, and any other TLA you can think of!

Here are extracts from the scripts:

 

On A at 01:00 (SNAP Creation)

 

$SSSU "FILE /opt/bc/smalogin" \
"ADD COPY \"Snap probkup\" DISK_GROUP=\"\Disk Groups\SNAP Disk Group\" REDUNDANCY=VRAID5 VDISK=\"\Virtual Disks\\$SOURCEAPP\backups\ACTIVE\" WORLD_WI
DE_LUN_NAME=6005-08b4-0010-46a9-0001-3000-1a7b-0000" >> $LOG 2>&1
#
$SSSU "FILE /opt/bc/smalogin" \
"ADD LUN 34 VDISK=\"\Virtual Disks\\$SOURCEAPP\Snap probkup\ACTIVE\" HOST=\"\Hosts\\$SOURCEAPP\\HATHOR\"" >> $LOG 2>&1

echo "coins Backups done" >> $LOG 2>&1
#

 

On B at 03:30 (SNAP mount)

 

ioscan -fnC disk
insf -e

 

vgchgid /dev/rdisk/disk649
vgimport vg_snap_probkup /dev/disk/disk649

vgchange -a y vg_snap_probkup
fsck /dev/vg_snap_probkup/lvol1
mount -r /dev/vg_snap_probkup/lvol1 /SNAP/probkup

 

on B at 22:00 (SNAP unmount)

 

umount /SNAP/probkup
vgchange -a n /dev/vg_snap_probkup
vgexport /dev/vg_snap_probkup

 

On A at 23:00 (SNAP deletion)

 

echo "\nDeleting "\\Virtual Disks\\$SOURCEAPP\\SnapClone of backups\" >>$DELETELOG
$SSSU "FILE /opt/bc/smalogin" "DELETE VDISK \"\Virtual Disks\\$SOURCEAPP\Snap probkup\ACTIVE\"" >> $DELETELOG

_____________________________________________

 

This is the sequence, and we want to increase the LUN size from 400GB to 500GB.

 

Regards

 

Tariq

Highlighted
Khairy
Esteemed Contributor

Re: LVM, EVA, and DLE, and any other TLA you can think of!

the script logic is pretty much straight forward.

if this is the case, you need to increase the size of LUN 6005-08b4-0010-46a9-0001-3000-1a7b-000​0 from 400GB to 500GB.

YOu can do this at the command view of the eva storage.

When this complete, at server A, you need to run ioscan and vgmodify. This is important so that LVM could detect and use the new disk capacity.
You can compare before and after the lun expansion with diskinfo command.

refer this example. h20000.www2.hp.com/bc/docs/support/.../c01920387.pdf

When you are done, you can extend your fileystem as usual.

You do not need to do any modification in the script. The script will create a snap of lun 6005-08b4-0010-46a9-0001-3000-1a7b-000​0.

The new snap size will follow exactly with whatever new size of 6005-08b4-0010-46a9-0001-3000-1a7b-000​0 has.

//
Highlighted
EU-Admins-UNIX
Regular Advisor

Re: LVM, EVA, and DLE, and any other TLA you can think of!

OK.

 

The 400GB SNAP lun is a snap clone of this volume below:

 

/dev/vg20/lvol1    419348480 358217512 61130968   85% /probkup

 

We need to increase this on the EVA as well.  

Highlighted
EU-Admins-UNIX
Regular Advisor

Re: LVM, EVA, and DLE, and any other TLA you can think of!

OK.  On Server A, our ultimate aim is to increase the volume below to 500GB.

 

The 400GB SNAP lun is a snap clone of this volume below:

 

/dev/vg20/lvol1    419348480 358217512 61130968   85% /probkup

 

We need to increase this on the EVA as well.  

 

This leads me to the question, if we just increase the size of this volume on Server A (Prod), will the SNAP clones automatically take the new size?

Highlighted
Khairy
Esteemed Contributor

Re: LVM, EVA, and DLE, and any other TLA you can think of!

yes. Your script will create similar size as your source LUN.

This script will work as long as your disk group have enough disk space for allocation.

 

PS: appreciate if you could assign some points to any of the posters.