hello need help configuring sas disks. with LSI 9260-8i controller card and 7 15k SAS hdd I only get 62 mb / s in Raid 0. I have tested the hdds individually with crystalmark the speed is 150-200 mb / s. I updated the firmware for LSI controller card. advices?
Is the raid configured in the controller firmware or is it a sofware raid?
Seven is not a power of two and some drives are writing at the same time more blocks than the others.
Every file system uses block size steps in a power of two.
If your stripe block size is 4 kb, then your ideal block size would be 7 x 4 kb = 28 kb which does not exist.
So assuming you are using the next higher power of two file system block size, then you will have 32 kb as minimal block and one drive has to write two 4 kb blocks while the other ones are all writing only one 4 kb block.
So use a power of two hdds for striping (raid 0), eg. 2, 4, 8, 16, 32, …
7 is a pretty odd number, maybe it’s a factor… However, I don’t think it needs to be strictly a power of 2. I have a 12 disk raid 0 that gets around 2 GB/s.
What filesystem are you using? On my 12 disk raid0, I’m using xfs with a separate logdev (though I don’t think the separate logdev matters).
I would recommend XFS for a raid0. XFS can take into account raid layout. If you are using mdadm, xfs will automatically detect the right values for the sunit and swidth (stride unit and stride width).
My LSI 92608i work on Windows10 with Broadcom drivers. I found the problem for slow speed. It was bad configuration in webbios Lsi. Now speed is good with 1500mb/s and More. I put eight 600gb on raid0. Hitachi 15k sas 3,5. Drives are very hot and i have to put good ventilation.
Thank you for your sévices