Re: Cache on hardware controller VS StarWind cache
Posted: Mon Oct 27, 2014 5:15 pm
There can be many reasons you see what you should not really see (performance degradation). One to start from are you using FLAT or LSFS containers?
Also please check why file copy is not a good performance test. See:
http://blogs.technet.com/b/josebda/arch ... stead.aspx
Also please check why file copy is not a good performance test. See:
http://blogs.technet.com/b/josebda/arch ... stead.aspx
adamrose045 wrote:We have some concerns, both of which relate to starwind write-back caching, on the disk performance penalty introduced by the SW SAN and shutdown scenarios requiring manual intervention.
1) With SW write-back cache enabled (on a 4 drive RAID 10 array on a Perc 6i with 512MB BBU), our large file 24GB copy write test to the SAN consistently starts out at 130 MB/sec but drops to under 50 MB/sec about halfway through (presumably when the write back cache is flushed). If we perform the same large file copy write on the native disk, it maintains about 100 MB/sec all the way through. File copy read tests with or without the SAN are each about 100 MB/sec. So it seems like the starwind SAN is introducing about a 50% write performance penalty hit vs. native disk - is this normal?