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sas multipath problem OI a7

R

RandyV

n00b
Joined
Apr 9, 2012
Messages
30
Hello all,

Maybe someone can shed some light on the following:
I have an OI storage (latest a7 update) with two LSI9207-414e cards and two AIC JBods (SAS 6G 24x3.5 4U 24-BAY) with expanders.
Disks are seagate 3TB disks (48 disks)

when the JBODS are connected per HBA to the storage (no multipath) then the speed is great (dd nears 2GB/s). The moment we connect them in a multipath capable manner, the speed drops to 40MB/s and less.

I have added :
device-type-scsi-options-list =
"SEAGATE ST33000650SS", "symmetric-option";

symmetric-option = 0x1000000;

to scsi_vhci.conf and rebooted with stmsboot -u. No change. stmsboot -e has already been done.

Has anaybody had any experience with this and found a solution for it. Maybe I have overseen something?

(BTW not a solaris guru.)

Rgds,
 
Hmm, that doesn't sound like a real enterprise disk, must be nearline or sata.

Most disk firmware/interposers don't support accessing the disk on multible paths at the same time. If the path changes, it dumps it's cache/commandqueue and starts over.

The defualt multipath setting is roundrobin, and this would result in very bad behavure.

reference: https://forums.oracle.com/forums/thread.jspa?messageID=9970550
 
Hi,
According to the specs, the Seagate Constellation ES.2 ST33000650SS are real SAS disks.
Thanks for the links, really interresting information

I guess I could try block load balancing. Anybody any experience with that?

Rgds
 
We have done some testing with the different scsi_vhci.conf settings. None seem to help.
Now we are also suspecting the Jbods from AIC. Thinking about switching to some supermicro type of JBOD.
Many threads about Jbods but what should I look out for when buying a (24Bay or 36Bay).
LSI=9207-414e
Maybe someone has good experiences with certain types and could tell me?

Rdgs
 
Now we have succeeded in applying the multipath using SuperMicro's Jbods. The only setting that works is the logical block load balancing. Nice speeds when it works with the sas drives. BUT....now we notice that when we pull one sas cable, the system doesn't continue through the remaining channel. We can plug it back in after which the drives are reachable again. If somebody knows of a setting that I have overseen, I hope you can tell me or give me a suggestion of where to look.. Mpathadm ofcourse show 2 available paths.

Rgds,

R
 
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