what drives to buy....?

mrbios · 29 Jun 2011 at 07:59

I've got a 16 bay Eonstor, currently 2 empty slots and 6 are filled with western digital 500GB RE2 drives.

The other 8 slots on the Eonstor are taken up by 2 x 4 drive RAID6 arrays of 2TB WD2001FASS-00U0B drives (the caviar black editions i think)

The top 8 drives are going to be used, for the next year at least, for storing virtual machines on for use with 5 vhosts running vmotion.

I'd like to go for the best drives possible but funds are an issue, can anyone recommend any drives that would sound ideal for this situation? (SATA2 please, luckily for our budget they aren't SAS)

mrbios · 29 Jun 2011 at 08:40

Sorry 8 drives is what im after, i want to replace the 500s with larger drives. Unsure what the end configuration will be regarding raid setup though at the moment.

mrbios · 29 Jun 2011 at 19:51

Yamahahahahaha said:
RAID6 is strongly recommended with 8+ drives.

The most important thing for storage drives is having a good (high) UBE (Unrecoverable Bit Error) rate .
Only look at drives with 10^15 or 10^16. Standard drives will have 10^14.

Keep in mind that virtual hosts may like IOPs, so it is definitely worth assessing how many are needed before you purchase these drives.
If the VMs are I/O intensive, you could even look at an SSD solution with models that have sufficient UBE rate.

I'd love SSDs but i can't see storage quality SSDs being anywhere near our price range, plus they'd likely be overkill for our requirements.

Where would i find the details on the UBE rates? These details don't seem to be listed with drives specifications on any websites im looking for stock on.

mrbios · 30 Jun 2011 at 07:46

AndrewP said:
Depending on the total space/exact performance requirements I'd go for the drives in RAID 10 or RAID 6, RAID 5 is a bit risky with the longer array rebuild times that come with bigger sizes.

That was my consideration actually, I've never used RAID10 before though, just RAID5 + RAID 6 (and obviously 1 and 0 individually)

If you have 8 disks in RAID10 as i understand it that'd give you roughly 4 x write and read speeds where as the others don't improve the write speeds? but how many drive failures would it allow? does it only allow 1 or does it allow up to 4 in an 8 drive array?