Ross Walker wrote: > On Nov 11, 2009, at 9:33 AM, "nate" <centos at linuxpowered.net> wrote: > >> carlopmart wrote: >>> Hi all, >>> >>> I have setup a raid1 between two iscsi disks >> Why would you think to attempt this? iSCSI is slow enough as >> it is, layering RAID on top of it would be even worse. Run RAID >> on the remote iSCSI system and don't try to do RAID between >> two networked iSCSI volumes, it will hurt performance even more. > > I think the OP was thinking storage subsystem redundancy. It's not > that bad of an idea since Linux RAID1 uses bitmaps for changed blocks > so the whole RAID1 doesn't have to be resilvered on a disconnect. > > ISCSI isn't that slow, I have found that it is only limiting for > extremely high bandwidth applications, but there is 10Gbe for those. > >>> Why md0 is not activated when I reboot this server? How can I do >>> this >>> persistent >>> between reboots?? >> Probably because the iSCSI sessions are not established when the >> software raid stuff kicks in. You must manually start the RAID >> volume after the iSCSI sessions are established. > > True, and I believe there is a initrd option for iSCSI devices at boot > that one can set in /etc/sysconfig/initrd if you apropos/grep/google > I'm sure you will find it. It's for iSCSI boot devices. > >> The exception would be if you were using a hardware iSCSI HBA >> in which case the devices wouldn't show up as iSCSI volumes they >> would show up as SCSI volumes and be available immediately upon >> booting, as the HBA would handle session management. > > True HW iSCSI would make sure they were available at boot, but CentOS > has had iSCSI boot device support since 5.1 one just needs the module > and tools in the initrd and there is an option for that. > > -Ross Thanks to all. i have reconfigured initrd to use iscsi disks and all works well. > _______________________________________________ > CentOS mailing list > CentOS at centos.org > http://lists.centos.org/mailman/listinfo/centos > -- CL Martinez carlopmart {at} gmail {d0t} com