Increase lun size which has fractional reserve

[GUVNIJJAR]

We have a volume with 800gb in size, and it has a lun with 400GB.   There is fractional reserve setup which is 100 %, so thats why the volume is 800 GB.

The lun is mapped to an esx server and is a vmfs datastore.

The lun is now running out of space, as the datastore has 3 GB disk left.

I want to increase the size of the lun.   So would i use the lun resize command with the increase amount.    is this the correct command to use.  Can some one advise on the syntax

Also before i increase the size of the lun, do i need to increase the size of  usable space on the volume because of the fractional reserve.  Can you confirm.

Thanks

[scottgelb]

If you are running snapshots then your fractional reserve is used and will take 800gb. Are you using snaps? You would use the vol size and Lun resize commands. Then add an extent in esx.

I would analyze your environment more though. Most often we don't use fractional reserve and also set the Lun guarantee to none. Them dedup can take the space savings back to the volume for more snaps or other Luns. Or to the aggr if the Flexvol is thin provisioned. Are you running Asis?

[GUVNIJJAR]

we longer need snaps, so have set the snap reserve to 0 as it was 20 5 before.

OK so i would use the lun resize command, so if i want to increase by 20 GB, i would use the command lun resize +20g,

also in esx, wouldnt i need to just scan my hba's and they would to pick up the new lun size, without needing to add an extent.

[scottgelb]

I would make space reserve 0 if you are not doing snaps… wasted space not needed or used. Rescan should see the space but I think you have to add the extent still.

[GUVNIJJAR]

thanks

but is the lun resize +10g syntax correct to increase the lun by 10 GB

[scottgelb]

That works… lun resize can be used similar to vol size where you specify a fixed value or the increment… +10g in your case. You might want to create a test lun, rescan it… then grow it and rescan to get the procedure down on a non-prod lun.

[GUVNIJJAR]

just one more question, if we dont need snapshots anymore for this volume, do we need to set fractional reserve for the luns, as from my understanding, fractional reserve come into play when you have snapshots.

[scottgelb]

Correct. You don't need it. Not used if no snaps

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