Thread: SAS RAID1 vs SAS RAID 10 vs SSD RAID 10 SPEED

Database servers like lots of RAM and fast disc subsystems.

But what is the difference in speed between the following?

SAS in RAID 1, SAS in RAID 10, SSD in RAID 10

Test Box:
Dual CPU Intel Xeon-Westmere X5675-Hexcore (12 cores, 24 with hyperthreading, hyperthreading enabled)
144GB RAM

To remove the RAM caching from the picture, before the tests, the system RAM cache was synced and disabled, and dropped every second via a shell script.

iozone command:

Code:

./iozone -R -l 20 -u 20 -r 4k -s 100m -F -+u /var/lib/mysql/iozone/f1 /var/lib/mysql/iozone/f2 /var/lib/mysql/iozone/f3 /var/lib/mysql/iozone/f4 /var/lib/mysql/iozone/f5 /var/lib/mysql/iozone/f6 /var/lib/mysql/iozone/f7 /var/lib/mysql/iozone/f8 /var/lib/mysql/iozone/f9 /var/lib/mysql/iozone/f10 /var/lib/mysql/iozone/f11 /var/lib/mysql/iozone/f12 /var/lib/mysql/iozone/f13 /var/lib/mysql/iozone/f14 /var/lib/mysql/iozone/f15 /var/lib/mysql/iozone/f16 /var/lib/mysql/iozone/f17 /var/lib/mysql/iozone/f18 /var/lib/mysql/iozone/f19 /var/lib/mysql/iozone/f20

Here is the results:

RAID 10 Stripe-unit size : 256 KB

Code:

                300GB 15K SAS   	200GB SSD         147GB 15K SAS 
                 RAID 1			RAID 10		  RAID 10
                 2 DRIVES               6 DRIVES          8 DRIVES
                 Adaptec 5805Z          Adaptec 5805Z     Adaptec 51645
  Initial write	 1,069,854 		1,188,887         1,124,733
        Rewrite  1,996,679 		2,998,885         2,399,090
           Read     90,659 		  673,914           146,407
        Re-read    103,601 		  757,921           232,513
   Reverse Read     23,770     		   94,985            30,889
    Stride read      3,901  		   98,771             4,422
    Random read      6,074 		  124,466            49,770
 Mixed workload  1,994,000              2,375,035         1,834,506
   Random write    535,259 		2,545,431         1,493,246
         Pwrite  1,271,305 		  962,715         1,155,852
          Pread    102,311 		  610,848           104,225

Max System Load        20                       8                14

I also did tests with larger file and block sizes, but I am showing these here as I am mostly interested in random small reads and writes (database).

I hope someone finds this interesting.

Warm regards.