On 2/07/10 06:49 AM, Marion Hakanson wrote:
On 06/21/2010 10:06 AM, Josh Simon wrote:
I'm seeing seriously degraded performance with round-robin SAS
multipathing. I'm hoping you guys can help me achieve full throughput
across both paths...
[email protected] said:
Hi Josh, I suggest logging a bug on bugs.opensolaris.org, using solaris /
driver / mptsas. Please include the info you sent in the earlier message too.
Has this bug turned up in the database yet? I want to file a "me too".
Except for us, this is Solaris-10U8 (not snv_134), and it's the mpt driver
(not mpt_sas).
Hi Marion,
different driver --> different bug.
Josh's bug is 6963122.
You should file a new one - bugs.opensolaris.org, Product Solaris,
Category kernel, Subcategory driver-mpt-x86.
I suggest looking at the public comments field for Josh's bug first,
though - the RE for that bug has some D you can run to help narrow
down the performance problem point.
cheers,
James
After seeing this problem report, I tried turning off the 2nd path on each
of the 2TB "Near-Line SAS" drives in our Dell MD1200 array. Sequential
write performance went up by 4.25 times. Making the same change to
an identical server with a J4400 and 1TB SATA drives resulted in only an
incremental improvement in bandwidth:
filebench fileio, multistreamwrite-1M:
MD1200, 2TB SAS, mpxio round-robin: 131 MB/sec
MD1200, 2TB SAS, mpxio static single: 557 MB/sec
J4400, 1TB SATA, mpxio round-robin: 427 MB/sec
J4400, 1TB SATA, mpxio static single: 498 MB/sec
Note that on the MD1200, with round-robin in effect, the drives were
showing 100%-busy with service-times in the 300 msec range. With the
static single-path in effect, service-times dropped to the 30 msec range.
The above numbers were observed on this type of pool layout (both systems):
NAME STATE READ WRITE CKSUM
f1b_zp1 ONLINE 0 0 0
raidz2 ONLINE 0 0 0
c5t5000C50014D641DDd0 ONLINE 0 0 0
c5t5000C50014D55B13d0 ONLINE 0 0 0
c5t5000C50014D5B9B4d0 ONLINE 0 0 0
c5t5000C50014D6EF76d0 ONLINE 0 0 0
c5t5000C50014D07BC2d0 ONLINE 0 0 0
c5t5000C50014D6DBA5d0 ONLINE 0 0 0
raidz2 ONLINE 0 0 0
c5t5000C50014D6CCB2d0 ONLINE 0 0 0
c5t5000C50014D6A126d0 ONLINE 0 0 0
c5t5000C50014D641BBd0 ONLINE 0 0 0
c5t5000C50014D65228d0 ONLINE 0 0 0
c5t5000C50014D6C530d0 ONLINE 0 0 0
c5t5000C50014D6E35Ed0 ONLINE 0 0 0
Regards,
Marion
--
James C. McPherson
--
Senior Software Engineer, Solaris
Oracle
http://www.jmcp.homeunix.com/blog
_______________________________________________
storage-discuss mailing list
[email protected]
http://mail.opensolaris.org/mailman/listinfo/storage-discuss
