Slow tape read-write after upgrade
Hi, all.
I had a server with Debian Lenny x64, with the old kernel 2.6.18 (it is
still from Etch). I upgraded all to Squeeze, with the native kernel
2.6.32. Everything worked well except the tape library HP StorageWorks
MSL 4048 Ultrium 960, connected to it via SCSI Megaraid 320-2x. It has
become very slow. If I had read/write speeds were about 40MB/s before
upgrade, now they are reduced to 1.5 MB/s. When the module "st" is
loaded i have a error:
[1186434.533759] st: Version 20081215, fixed bufsize 32768, s/g segs 256
[1186434.535595] st 2:1:4:0: Attached scsi tape st0
[1186434.535619] st 2:1:4:0: st0: try direct i/o: yes (alignment 4 B)
[1186435.276372] scsi_id[774]: segfault at 0 ip (null) sp
00000000ffdff520 error 14
[1186435.953466] scsi_id[777]: segfault at 0 ip (null) sp
00000000ffa00a20 error 14
I checked speed by "tar" and "dd". When reading from a device (such as
a "dd"), the "dd" process working with status "D" that is i/o wait. In
the "top" load average starts to increase, and then kept stable more
than 1. This low speed of read/write does not suit me. Can you tell what
I can to tweak? Thanks.
WBR, Iurii O Tabolin.
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