Messages in this thread |  | | From | Rainer Krienke <> | Subject | 2.4.19: Strange raid1 resync problem with raid1 on top of multipath raids | Date | Tue, 4 Feb 2003 13:55:42 +0100 |
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Hello,
I am running smp Kernel 2.4.19 (from SuSE: k_smp-2.4.19-210) on a machine that is connected by a fibrechannel fabric to several hardware raid (5) devices. There are two paths to each partition on the hardware raids. I want to have a mirror on two of the hardware raid5 devices (I know this is very redundant). Since each hardware raid can be reached along two different paths (across two fc-switches) I would like to use a multipath config.
So I configured a raid1 device on top of two multipath raid devices like shown below in a part of /etc/raidtab. Generally things work just fine. However there is one big problem: The resync speed for the raid1 device is only about 1MByte/sec. Because of the size of the array (~900GBytes) resyncing would take about 30Days! If I omit the multipath configuration and just specify a simple raid1 across the two hardwareraid disks, resync speed is at about 60MBytes/sec which is normal.
Is this a known problem? Is there a patch to get things right?
Thanks very much Rainer
--------------------------------------------------------------- /etc/raidtab The devicenames are aliases from scsidev so do not wonder. sw0, sw1 represent the fc-switches by which the raid devices are connected to the host. There is one path over sw0 to a disk and another over sw1 to the same disk. --------------------------------------------------------------- raiddev /dev/md5 raid-level multipath nr-raid-disks 1 nr-spare-disks 1 chunk-size 4 device /dev/scsi/sw0d0l0-p1 raid-disk 0 device /dev/scsi/sw1d0l0-p1 spare-disk 1
raiddev /dev/md6 raid-level multipath nr-raid-disks 1 nr-spare-disks 1 chunk-size 4 device /dev/scsi/sw0d1l0-p1 raid-disk 0 device /dev/scsi/sw1d1l0-p1 spare-disk 1
raiddev /dev/md7 raid-level 1 nr-raid-disks 2 nr-spare-disks 0 chunk-size 4 persistent-superblock 1 device /dev/md5 raid-disk 0 device /dev/md6 raid-disk 1
-- --------------------------------------------------------------------------- Rainer Krienke, Universitaet Koblenz, Rechenzentrum Universitaetsstrasse 1, 56070 Koblenz, Tel: +49 261287 -1312, Fax: -1001312 Mail: krienke@uni-koblenz.de, Web: http://www.uni-koblenz.de/~krienke Get my public PGP key: http://www.uni-koblenz.de/~krienke/mypgp.html ---------------------------------------------------------------------------
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