Hello The performance difference between SAS and SATA may be due to drive cache. I think drive cache on SATA is enabled by default and disabled by default on SAS. The results of short tests could be greatly affected by drive cache. [URL] Thanks
I have a r710 with a h700 and 6x Seagate ST33000650SS - Seagate 3TB. I have configured the hdds configured in a raid 6 with strip size 64k and write through (performance is of course better with write back). To try the performance I use dd with oflag=direct. I get the following performance after the array is initialised: # dd if=/dev/zero of=tempfile bs=4k count=1000 oflag=direct1000+0 records in1000+0 records out4096000 bytes (4.1 MB, 3.9 MiB) copied, 10.0365 s, 408 kB/s   # dd if=/dev/zero of=tempfile bs=64k count=1000 oflag=direct1000+0 records in1000+0 records out65536000 bytes (66 MB, 62 MiB) copied, 10.8298 s, 6.1 MB/s   # dd if=/dev/zero of=tempfile bs=1M count=1000 oflag=direct1000+0 records in1000+0 records out1048576000 bytes (1.0 GB, 1000 MiB) copied, 32.6076 s, 32.2 MB/s   # dd if=/dev/zero of=tempfile bs=1G count=1 oflag=direct1+0 records in1+0 records out1073741824 bytes (1.1 GB, 1.0 GiB) copied, 3.25547 s, 330 MB/s   I have tried the same with a consumer grade SATA disk and get a lot higher speed for 4k and 64k and I would expect at least the same speed with the SAS disks.   Any thoughts about the performance? I have tried the disks without being in an array but then I forgot to wait for the initialisation to finish so I'll need to redo that test.   Some information about h700: Versions================Product Name : PERC H700 IntegratedSerial No : 15I013UFW Package Build: 12.10.7-0001 Mfg. Data================Mfg. Date : 05/20/11Rework Date : 05/20/11Revision No : A04Battery FRU : N/A Image Versions in Flash:================BIOS Version : 3.18.00_4.09.05.00_0x0416A000FW Version : 2.100.03-4651Preboot CLI Version: 04.04-010:#%00008Ctrl-R Version : 2.02-0025.1NVDATA Version : 2.07.03-0003Boot Block Version : 2.02.00.00-0000BOOT Version : 01.250.04.219
Slow hard disk speed on dell r710 with h700 and seagate disks