2 Iron

snap view mount issues

i have a host - hpux 11.0 , cx 3-80
3 LUNS - lun 1 , 2 , 3 (already have file systems and lots of free space on VG's)
i use clarion snaps .

last night , i need to recover something from snap , so i created 4 files systems using above LUNS . i mounted the snap luns on the same host
and started copying from snap luns (which i mounted ) to newly created file systems . After copying for about 2-3 hours , i started seeing some i/o error on the system . I checked the navi and founf that my session associated with the LUN are gone . I just the navi log and found out that the Snap LUN got full (100%) and probably clariion removed them due to some integrity issues.

I think i figure out that it is not practice to mount the snap on the same host but like to know your opinion and some root cause.
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5 Replies
5 Rhenium

Re: snap view mount issues

when a snap session runs out of space on the reserve LUN and there are no additional reserve LUNs available, snap when end the session. You need to create more reserve LUNs.

You should not have both the source LUN and the snap mounted on the same host.

Below is a article about reserve LUNs

Reserve LUNs

White Paper: EMC CLARiiON Reserved LUN Pool Configuration Considerations - Best Practices Planning

http://powerlink.emc.com/km/live1/en_US/Offering_Technical/White_Paper/H1585_clariion_resvd_lun_wp_l...

glen
2 Iron

Re: snap view mount issues

so if i have to do it again

i can mount the snap lun to the different a different host . but i still need to perform copy and this will again increase the writes and grow the snap reserved luns . Is there a way i can stop the changes from happening to my Snap LUNS while iam doing the copy . This way i don't have to worry about the filling my reserver snap luns .
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7 Thorium

Re: snap view mount issues

if you must mount snapshots/clones on the same host as the source volume, make sure to use vgchgid before you import the disk. You can use this solution, even though it talks about BCVs, you need to pefrom the steps on your target devices.

6.0.90195.1757828
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4 Beryllium

Re: snap view mount issues

also while doing vgchgid make sure you select all LUNs from same VG at a time
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2 Iron

Re: snap view mount issues

i think i figure out the issue . next time i need to use seperate LUN which is outside the snap . so that way my write will not impact the changes to my snap . lesson learned .
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