Disk array addition

David Cruanyes Lee — Mon, 21 Jan 2002 10:00:07 GMT

Hi,

We have an Autoraid in an hp-ux 11.00, with two unused disk devices. Which is the best procedure to configurate them?
(SAM->Disk Devices (Select)->Actions -> Configure ?? using LVM, anything else I should consider?)

Re: Disk array addition

Bill McNAMARA_1 — Mon, 21 Jan 2002 10:36:49 GMT

Well, long story with the autoraid..

run arraydsp -a
where arrayid is the number returned from arraydsp -i

This will tell you all the disk info of the array.

The autoraid disks are effictively (although not exactly) grouped together into N+1 configuration to prevent against data loss in case of a failed disk.. thus you really don't have a single disk visible to your host but what's called a LUN.

The last digit of the device file /dev/dsk/cXtYdZ (ie the Z) is the lun number.

If you have two controllers connected to your array there could be two device files for the same lun.. thus it may not be used, but may be used.. if you catch my drift.

A LUN is treated by the OS as a disk like any other (except you get the Z number not necessarily equal to 0 as with standalone disks)

Thus you can go to SAM LVM configuration and create a PV.
Add that PV into a VG and use the disk space by creating an LV in that VG (on that PV).

If the disk is in use you will get an error and will have to pvcreate -f to create the PV... but remember it could be the alternate path to a LUN in use and effective with the -f command you've made you data virtually impossible to restore.

strings /etc/lvmtab to figure out which PV (lun or disks) are in each VG.
And then with ioscan -fnkCdisk figure out if these PVs are AutoRaid Luns.. it's up to you the to figure out if they are indeed available.

Later,
Bill

Re: Disk array addition

Craig Rants — Mon, 21 Jan 2002 14:34:39 GMT

One correction to Bill's statement if I may.

If the array disk has been used before, there is an array command to use, not pvcreate -f

arraycfg -D A2 {or whatever disk slot} -a 00000F23423 {or whatever serial number}

That will remove the previously configured info on the disk and allow it you be used in the autoraid.

GL,
C

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Disk array addition

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