topic Re: AutRaid in Disk Enclosures

AutRaid

augusto cossa — Wed, 04 Jul 2001 04:20:25 GMT

Good Day,

We have an HP AutRaid 12H unit with 8 by 18GB hard drives installed.

The installation engineer has configured all 8 LUN's utilising the total
disk space on the unit.

As there are still 4 spare slots, we intend installing additional disks - the
question is : what LUN will we assign these disks to ?

Is it possible to extend the existing LUN's ?

Can we configure more than the 8 LUN's limit displayed by command 'arraydsp' ?

Many thanks......

Augusto

Re: AutRaid

Rainer von Bongartz — Wed, 04 Jul 2001 05:03:01 GMT

Augusto,

Well I would say you are in trouble here!!!!

You definetly cannot assign more than 8 LUN's and you cannot extend a LUN ( at least this is the information I got from HP a year ago)
Your installation engineer sure did not do a good job here assigning 8 LUN's to 8 disks.

Only thing you can do is to backup, break up the volume groups assign new LUN's and VG's and recover.

I must confess: not a nice job to do

Good luck
Rainer

Re: AutRaid

JAYAMOHAN.V.D — Wed, 04 Jul 2001 05:19:33 GMT

hi,
its not possible to extend the existing LUNs. You need to reconfigure the entire LUN structure. before doing this , u should hv a full backup of the data.
Its better to keep in mind that more than 8 luns are not supported and thus, try not to reach this max value if u r planning for future upgradation.
regards
jayamohan

Re: AutRaid

Bill McNAMARA_1 — Wed, 04 Jul 2001 06:39:35 GMT

You're out of luck.
You can use that extra disk space to increase performance though..
You will have to recreate the lun (delete create) re-pvcreate and then vgcreate.

This is not specific to the autoraid, all disk arrays do not allow a lun size increase.

Later,
Bill

Re: AutRaid

Varghese Mathew — Wed, 04 Jul 2001 07:17:55 GMT

Hi Augusto,

All the above answers are right, you are really in a bad shape.. Still you can plan in future, learning from the first experience..

Cheers !!!
Mathew

Re: AutRaid

Insu Kim — Thu, 05 Jul 2001 04:06:37 GMT

You can't configure more than 8 LUNs in AutoRAID.
Unfortunatly, you have to back up your data first and delete all the existing LUN(s) and create LUN(s) again.

By the way, from performance standpoint, there're something that you have to consider when you create LUNs.

1. The more RAID 0/1 space available, the better disk array performance.
You can achieve this by increasing the amount of unallocated capacity on the disk array.

2. Enabling active hot spare.
It's because it's used as RAID 0/1 space until a disk fails.

3. Proper disk module installation.
Must be installed from left to right and bottom and down.
The reason is that disks will be spreaded across the internal SCSI buses and balances the I/O load.

Hope this helps,