unRaid and SSD

[p13]

Hi,

 

Have done some tests with latest unRaid and SSDs and got some surprising results. No meter how good SSDs are, write speed of unRaid never reaches network maximum. From the other hand, same hardware running under Windows 7 does. What's wrong?

 

Some details:

- used SATA3 SSDs on PCI-E2 add-on cards, which in Winows show >350 MB/s read and >250 MB/s write internal access speed (large sequential).

- Before each test (including unRaid), drives are forcely TRIMed (reset as new). So no SSD segmentation is occurring.

- unRaid is not even configured for parity at all (neither user shares enabled), just simple drives, so performance drop is not because of parity writing.

- when writing to shared drive under Windows 7 got read/write speed of 115 MB/s (which is 1 Gb network limit), means drives do function correctly to their full capacity.

- when writing to same shared drive under unRaid got 75 MB/s write only (that's on large sequential). Things getting even worth on small files. When doing the same with parity enabled (also SSD), performance drops down to 56 MB/s...

 

Frustrating...

Is there any special tuning/trick needed in order to make SSDs work to their full capacity under unRaid? Or such performance drop comparing to W7 is sort of "normal"?

Thanks for giving any ideas...

 

[darkside40]

Have you tried the SSD on the Sata Ports of your Mobo?

Maybe the drivers for the PCI-E Card you are using is not optimized under unRaid?

 

What hardware do you use?

[bubbaQ]

I get full Network speed to and from unRAID with SSDs.  http://lime-technology.com/forum/index.php?topic=23539.msg207541#msg207541  I also can get full network speed to spinners, when there is a HW RAID-0 underneath unRAID.

 

Are you writing to User Shares or Disk Shares?

 

What "PCI-E2" controller are you using?

 

Did you use aligned or unaligned partitioning?

 

What is parity check speed?

[seanant]

Where do I read about Raid 0 under unraid?