> 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). 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 _______________________________________________ storage-discuss mailing list [email protected] http://mail.opensolaris.org/mailman/listinfo/storage-discuss
