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Wednesday, September 29, 2010
iPad 3G, do I need this?
Tuesday, September 14, 2010
Hardware RAID vs Software RAID
On the recent few server launches, we have acquired one of the latest hardware RAID card from LSI (LSI 3ware SAS9750-4i). So, it's time for a test.
Server specs:-
1 x Intel Xeon 5504
4GB DDR3 ECC RAM
RAID hardware: LSI 3ware SAS9750-4i
Configuration: RAID5
Hard Disk: 3 x 500GB WD RE3
[root@localhost ~]# dd if=/dev/zero of=test.img count=300 bs=10M
300+0 records in
300+0 records out
3145728000 bytes (3.1 GB) copied, 106.22 s, 29.6 MB/s (writing speed)
[root@localhost ~]# dd if=test.img of=/dev/null bs=10M
300+0 records in
300+0 records out
3145728000 bytes (3.1 GB) copied, 1.18725 s, 2.6 GB/s (reading speed)
And it's time to test the rebuild speed. HOT pull out one of the Hard Disk and insert it back to rebuild. The rebuilding time was about 2hrs for 500GB drive
------------------------------------------------------------------------------------
RAID hardware: None, mdadm
Configuration: RAID1
Hard Disk: 2 x 500GB WD RE3
[test@localhost ~]$ dd if=/dev/zero of=test.img count=300 bs=10M
300+0 records in
300+0 records out
3145728000 bytes (3.1 GB) copied, 30.1198 s, 104 MB/s (writing speed)
[test@localhost ~]$ dd if=test.img of=/dev/null bs=10M
300+0 records in
300+0 records out
3145728000 bytes (3.1 GB) copied, 10.175 s, 309 MB/s (reading speed)
------------------------------------------------------------------------------------
Configuration: RAID0
Hard Disk: 2 x 500GB WD RE3
300+0 records in
300+0 records out
3145728000 bytes (3.1 GB) copied, 13.5305 s, 232 MB/s (writing speed)
[user@localhost ~]$ dd if=test.img of=/dev/null bs=10M
300+0 records in
300+0 records out
3145728000 bytes (3.1 GB) copied, 1.0086 s, 3.1 GB/s (reading speed)
------------------------------------------------------------------------------------
Comparison:
RAID1 is my favorite setup as it has the balance on all factors (space, reliability, performance) due to its simplicity, reliability and performance. RAID1 setup is recommended for simple and basic server setup.