On Oct 26, 2011, at 7:56 PM, weiliam.hong wrote:
> Questions:
> 1. Why does SG SAS drives degrade to <10 MB/s while WD RE4 remain consistent 
> at >100MB/s after 10-15 min?
> 2. Why does SG SAS drive show only 70+ MB/s where is the published figures 
> are > 100MB/s refer here?

Are the SAS drives multipathed? If so, do you have round-robin (default in most 
Solaris distros) or logical-block?

> 3. All 4 drives are connected to a single HBA, so I assume the mpt_sas driver 
> is used. Are SAS and SATA drives handled differently ?

Yes. SAS disks can be multipathed, SATA disks cannot.
 -- richard


ZFS and performance consulting
LISA '11, Boston, MA, December 4-9 

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