[email protected] said: >[email protected] said: >> 3 properties can be edited in mpt.conf to tune the performance: >> . . . >> mpt_doneq_length_threshold_prop - default 8 > > Thanks for the suggestion, I'll give this a try today. I expect that since > the V245 has only two single-core CPU's, there's not a lot of help to be had > with this approach, but it still sounds encouraging.
Problem is resolved, without applying any settings of any kind. Turns out the V245's SERVICE light was lit, but there were no hardware faults to be found. Only the occasional entry in /var/adm/messages: Aug 4 08:22:44 myslowhost rmclomv: [ID 647266 kern.warning] WARNING: SC is not responding Aug 4 09:07:44 myslowhost rmclomv: [ID 647266 kern.warning] WARNING: SC is not responding Aug 4 11:56:47 myslowhost rmclomv: [ID 714237 kern.notice] NOTICE: SC recovered I shutdown the OS, removed power from the chassis, then re-powered it, which allowed the SC to cold-start. After rebooting the system, the slow I/O was gone. Fixed by rebooting -- kind of embarrassing. Note that while the problem was present, I/O on both the SAS HBA (mpt0) and the internal SAS controller (mpt1) were affected, and it's possible that other drivers may have been involved as well. I can only guess that while handling mpt interrupts, the kernel went off in some SC-related direction; perhaps the rmc_comm driver was nonresponsive and slowing everything else down. If I'd been better versed in DTrace, I'm sure it would've been obvious. Oh, by the way, I did try my simple "dd" write tests both with and without these "mpt_doneq_*" settings in place: mpt_doneq_thread_n_prop = 8; mpt_doneq_length_threshold_prop = 8; mpt_doneq_thread_threshold_prop = 10; I couldn't measure any difference in performance. It's possible that the simple "dd" test did not load the system enough for the I/O completion fanout feature to kick in, and/or that two CPU cores is not enough to really take advantage of it. Thanks again for the assistance, Marion _______________________________________________ storage-discuss mailing list [email protected] http://mail.opensolaris.org/mailman/listinfo/storage-discuss
