topic Re: Query on Mirrored boot disk failure in Operating System - HP-UX

Query on Mirrored boot disk failure

Rg_4 — Thu, 05 Aug 2010 11:09:44 GMT

Dear All,

Pls clear my doubt,

1. In a running server if primary boot mirrored disk failed,then server will restart or not?
2. what will happen to running server If alternate boot disk of mirrored vg00 failed

Thanks in Advance
Ragesh

Re: Query on Mirrored boot disk failure

Torsten. — Thu, 05 Aug 2010 11:31:16 GMT

1) No, it using the other disk

2) if the other disk is still dead?
Your server cannot run without a boot disk.

if 1 disk remains working, your server will continue, no matter which disk is died.

Re: Query on Mirrored boot disk failure

rariasn — Thu, 05 Aug 2010 11:38:20 GMT

Hi,

Hi:

Other considerations:

Three corollaries to the mirroring recommendation are:

1. Use the strict allocation policy for all mirrored logical volumes. Strict allocation forces mirrors to occupy different disks. Without strict allocation, you can have multiple mirror copies on the same disk; if that disk fails, you will lose all your copies. The allocation policy is controlled with the â s option of the lvcreate and lvchange commands. By default, strict allocation is enabled.

2. To improve the availability of your system, keep mirror copies of logical volumes on separate I/O busses if possible. With multiple mirror copies on the same bus, the bus controller becomes a single point of failureâ if the controller fails, you lose access to all the disks on that bus, and thus access to your data. If you create physical volume groups and set the allocation policy to PVG-strict, LVM helps you avoid inadvertently creating multiple mirror copies on a single bus. For more information about physical volume groups, refer to lvmpvg(4).

3. Consider using one or more free disks within each volume group as spares. If you configure a disk as a spare, then a disk failure causes LVM to reconfigure the volume group so that the spare disk takes the place of the failed one. That is, all the logical volumes that were mirrored on the failed disk are automatically mirrored and resynchronized on the spare, while the logical volume remains available to users. You can then schedule the replacement of the failed disk at a time of minimal inconvenience to you and your users. Sparing is particularly useful for maintaining data redundancy when your disks are not hot-swappable, since the replacement process may have to wait until your next scheduled maintenance interval.

rgs,

Re: Query on Mirrored boot disk failure

Deeos — Thu, 05 Aug 2010 11:40:12 GMT

1. No, server will use another disk without any hamper!

2. No matter of primary or alternete disk failure, your one of the mirrored disk should active for any fault tolerance!

Regards
Deeos

Re: Query on Mirrored boot disk failure

Emil Velez — Thu, 05 Aug 2010 13:15:25 GMT

boot up with hpux -lq

if a disk fails either the mirror or primary you will get a LVM message in the syslog.

Then fix it !

Re: Query on Mirrored boot disk failure

Torsten. — Thu, 05 Aug 2010 13:20:47 GMT

It continues to run even if the system is booted without "-lq".

But you need to use "hpux -lq" if you want to reboot the server with a dead disk installed.

Re: Query on Mirrored boot disk failure

Deeos — Thu, 05 Aug 2010 13:35:59 GMT

As per the above torston comment!

it's exactly like that!

Regards
Deeos

Re: Query on Mirrored boot disk failure

Rg_4 — Mon, 08 Nov 2010 13:21:35 GMT

Thx