Never install 7,200 RPM drives as OS or Database Drives
Never create a 3 Drive RAID 5 (Even with 15k Drives)
Never create a 4 Drive RAID 5 with a host spare (This is a 3 Drive RAID 5)
Never create a 4 Drive RAID 5 with 10k or 7.2k Drives
Always opt for 3.5” drives over 2.5” drives (3.5” 15k drives cost the same as 10k)
5K Drives are 10% faster than desktop drives, 0K drives are only 0% fasterAlways add all Disks to your RAID then create LUNS to partition the data
IOPs = ((RPM/1000)/(Latency*Seek))*SPINDLE COUNT
Average IOPs
- 7,200 RPM = 75-100 (75 avg.)
- 10,000 RPM = 100-150 (125 avg.)
- 15,000 RPM = 150-200 (175 avg.)
Never use RAID 6 or RAID 5 in Write Intensive Applications
RAID 6 has the Highest I/O Write Impact, RAID 5 Second Highest
I/O Impact
- RAID 0 – 1:1
- RAID 1 /10 – 2:1
- RAID 5 – 4:1
- RAID 6 – 6:1
2 Cores,
92 GB of Ram and a Drive RAID 5 with ANY drives = FAIL
Don’t forget that read errors (URE) affect RAID more than most people think.
If we were to lose a single drive, and any of the surviving drives experience an unrecoverable read error (URE), the entire array will fail.
http://forums.storagereview.com/index.php/topic/34094-is-raid-56-dead-due-to-large-drive-capacities/
As drives increase in size, any drive failure will always be accompanied by a read error. So RAID 6 will give you no more protection than RAID 5 does now, but you’ll pay more anyway for extra disk capacity and slower write performance.
http://www.lucidti.com/zfs-checksums-add-reliability-to-nas-storage