topic Re: Linux - XP1024 - Failover using LVM PVLinks? in Operating System - Linux

Linux - XP1024 - Failover using LVM PVLinks?

Kermes78 — Tue, 08 Apr 2008 10:17:33 GMT

Good morning,
is there any way to reach failover funcionality using Linux RHEL5 lvm with a couple of paths to one XP1024 LUN?

Some info:
[root@svl06 ~]# cat /proc/scsi/scsi
Attached devices:
Host: scsi0 Channel: 00 Id: 00 Lun: 00
Vendor: HP Model: OPEN-E*15 Rev: 2114
Type: Direct-Access ANSI SCSI revision: 02
Host: scsi1 Channel: 00 Id: 00 Lun: 00
Vendor: HP Model: OPEN-E*15 Rev: 2114
Type: Direct-Access ANSI SCSI revision: 02

These corresponds to /dev/sdb and /dev/sdd devices. I've checked them (same LUN, just different path using SANsurfer from Qlogic)

We have one VG using one of the PVs:
--- Physical volumes ---
PV Name /dev/sdb1
PV UUID zytcmV-fa9l-tsKi-FVCF-2MXV-ektu-r7t2a1
PV Status allocatable
Total PE / Free PE 52097 / 1

The problem is that we can't add the second PVLink, as we normally do in HPUX, to the VG:
[root@svl06 ~]# vgextend vg02 /dev/sdd1
/dev/sdd1 not identified as an existing physical volume
Unable to add physical volume '/dev/sdd1' to volume group 'vg02'.

Any comment is really welcomed!

Re: Linux - XP1024 - Failover using LVM PVLinks?

Heironimus — Tue, 08 Apr 2008 17:58:47 GMT

pvlinks is an HP-UX thing. These days the two standard methods for doing it on Linux with qlogic cards are the qlogic driver's built-in failover and the dm-multipath generic multipath driver. I think qlogic and the Linux distributions are pushing toward dm-multipath as the standard solution, but qlogic failover has been around longer (Red Hat only added dm-multipath in RHEL4u2).

Re: Linux - XP1024 - Failover using LVM PVLinks?

Kermes78 — Wed, 09 Apr 2008 05:25:33 GMT

Thanks for your answer!

We will try to use one of that methods... qla2xxx or dm-multipath.

Thanks!

Re: Linux - XP1024 - Failover using LVM PVLinks?

skt_skt — Thu, 10 Apr 2008 10:36:32 GMT

other option would be power path/secure path which ever is applicable. We use PP with EMC storages.

Re: Linux - XP1024 - Failover using LVM PVLinks?

Heironimus — Thu, 10 Apr 2008 18:23:08 GMT

You'd probably want PowerPath if you had an EMC. You can also use qlogic's SanSurfer for some additional load balancing options with the qlogic driver. HP's SecurePath, however, was pretty much a dead product the last time I looked - HP had no plans to support 2.6 kernels and said to use the qlogic failover driver (they had an HP-certified package).