On 3/07/10 02:48 AM, Marion Hakanson wrote:
j...@opensolaris.org said:
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.
If I interpret the bug report correctly, it's been closed, having been
diagnosed as a function of HBA or drive firmware, not a driver issue.
Yes, that's correct.
I went looking for an easier workaround than manually disabling every
drive's second path using "mpathadm disable path ...", and stumbled
across "load-balance=logical-block" as a possibility.
http://sunsolve.sun.com/search/document.do?assetkey=1-61-206894-1
http://sunsolve.sun.com/search/document.do?assetkey=1-61-202693-1
I gather that mpxio with "load-balance=round-robin" makes these drives
go slow because the drive waits for one revolution before it can switch
ports/paths to handle next command from the host.
That's correct.
Probably does away
with the drives command-queue, too.
Pretty sure that's not the case.
Spent a good chunk of yesterday testing a number of different region-size
settings with "load-balance=logical-block", finding that basically anything
is much better than the default "load-balance=round-robin", but nothing is
as good as "load-balance=none".
That's really good to know, thankyou.
Best performance of all was after manually assigning half the drives to
use one path, and half to use the other path. I now find myself wishing
there was a "load-balance=<something>" setting which would do this
automatically.
If you log an RFE for it (solaris/kernel/io-multipath) then there's
a decent chance it could get implemented :-)
I speculate that this is what the LSI RAID-controllers
must do to provide their redundant-path load-balance functionality.
No idea on this, sorry.
Very glad to hear you've made progress. I'm going to try the
logical-block load balance setting on my workstation at home.
It'll be an interesting experiment I'm sure!
best regards,
James
--
Senior Software Engineer, Solaris
Oracle
http://www.jmcp.homeunix.com/blog
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