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Just looking at a new hard drive for use in the home server, and was wondering if anyone knew what the reliability is like on 2.5in drives?
I don't need that much capacity so I could use either size, there is room in the case for 3.5in drives but the world seems to be heading in the 2.5in direction.
3.5" is cheaper per GB, so I don't see why you would want to go for a 2.5" if you have room for a 3.5".Quote:
Originally Posted by DanceswithUnix
Reliability, if they really are better. If nothing else, the airflow around a smaller drive would be better.
5.25" drives used to be cheaper per GB than 3.5" drives but they still died out. In a few years I expect 3.5" drives will be only for high capacity drives and mainstream will be 2.5"
Also, I can get a 4 drive raid array in the space of 1 DVD bay:
http://www.scan.co.uk/products/icy-d...lane-raid-cage
Am edging towards a pair of WD 3.5" red drives mirrored, but still unsure atm.
Or indeed 6 drives.........Quote:
Originally Posted by DanceswithUnix
http://www.scan.co.uk/products/icy-d...lane-raid-cage
Reliability wise, I haven't a clue though.
Blimey, I hadn't looked that far down the list. I think at six drives I would want to be using enterprise class stuff so they didn't vibrate each other into early failure though and I don't have that much money :)
Been having another look at pricing. The cheapest 500GB drive on Ebuyer is 2.5":
http://www.ebuyer.com/339424-hitachi...-drive-0j11285
Really hard to get a direct comparison but comparing two Hitachi drives 1TB at 3.5" is £53, at 2.5" £60 so not that much in it:
http://www.ebuyer.com/177466-hitachi...ds721010cla332
http://www.ebuyer.com/363299-hitachi...-drive-0j22413
Now those 2.5" drives are only 5400rpm so will be slower, but then if I cared about performance that much I would probably be getting an SSD.
2.5" drives at 7200rpm seem to be much lower capacity and about a pound a gig, but 4.2ms seek is rather nice:
http://www.ebuyer.com/255282-wd-500g...ive-wd5000bpkt
I think I am just confusing myself with options now :D
Its over 1TB the prices start diverging in favour of 3.5" drives. 2TB 3.5" drives start around £70 whilst the 2.5" drives cost much more.Quote:
Originally Posted by DanceswithUnix
Indeed. But that's half the fun! :)Quote:
2.5" drives at 7200rpm seem to be much lower capacity and about a pound a gig, but 4.2ms seek is rather nice:
http://www.ebuyer.com/255282-wd-500g...ive-wd5000bpkt
I think I am just confusing myself with options now :D
Thankfully I don't need more than 1TB of storage, though some redundancy would be excellent. So:Quote:
Originally Posted by badass
2 x 1TB 3.5" drives = £105.60 for 1TB mirrored
3 x 0.5TB 2.5" drives = £105.96 for 1TB raid 5/raid z.
though I probably would want one of those natty 2.5" quad bays if I went that route that does bump the price a lot.
Still confused :)
Given that a lot of servers ship with 2.5" SAS drives, I can't imagine there's a problem.
Also, any statistics are likely to be skewed by the fact that they're usually used in laptops where temperatures are likely to be much higher - if such statistics even exist.
I'm currently using a 2.5" disk instead of 3.5" in my main machine, but my experience after 15 months is pretty irrelevant, and even then it's a sample size of one. When I have dealt with large numbers of machines, I can't say I've seen any preference towards 2.5" in terms of failure rates, which is a little surprising given the additional abuse they took.
You mean ~10p/GB, not £1/GB. :P
Don't confuse enterprise 2.5" SAS drives with consumer 2.5" drives as they're not really comparable, the former use a different form factor and are designed with low access times and high reliability in mind.
However, I don't think you'll have any problems using 2.5" drives for network storage, there are also off-the-shelf NAS devices designed specifically for them. 2.5" drives should run more quietly and use less power, but if those aren't important to you, you're probably better off with 3.5" drives for the better cost/GB.
Something to bear in mind with 2.5" drives, they often use aggressive head parking by default as they're designed for mobile use where they'll be moved around a bit, but the head park count can quickly rise. I've not heard of any drives failing as a direct result of it but I prefer to disable it or set the timeout much higher where possible.
As shown above the price penalty for using 2.5" drives is 36p. As a fraction of ~£105, I think I can wear that :DQuote:
Originally Posted by watercooled
Three drives, even if those drives are a bit slower, are usually faster than 2 drives.
If I want to do it properly, I would want to spend more to get the drives in caddies. Looking at the caddies available, they look like they have 40mm fans built in the enclosure so they would require modding to get acceptable noise levels. Time is a bit tight atm else I would quite fancy a bit of metalwork.
That's an interesting point I hadn't considered, thanks!Quote:
Something to bear in mind with 2.5" drives, they often use aggressive head parking by default as they're designed for mobile use where they'll be moved around a bit, but the head park count can quickly rise. I've not heard of any drives failing as a direct result of it but I prefer to disable it or set the timeout much higher where possible.
Well, raid 3/5/6/50/60 (and their variants) will normally write slower but read faster than raid 1.....So the mirrored pair could be better in a write-heavy scenario.
The 2.5" drives are hard to compare directly to 3.5" drives for performance. While you lose the super-high density of the outer half of the 3.5" drive, you do gain the short-stroke nature of the 2.5".....how that plays out will be a combination of what drives you choose and what their workload is like. No easy answer there :(
Also, 2.5" SATA drives are (IMO) fairly crappy.....while 2.5" SAS drives are ridiculously priced.
Personally, if I was building from scratch with my current knowledge I would consider a ZFS volume of high capacity 3.5" drives with a 120/240GB SSD cache (120/240GB as most of them have the considerably better garbage collection compared to the 128/256GB models, making them better in a RAID environment).
I have been edging towards zfs, but under Linux it seems a bit of a risk and right now I don't think I have the time to set up anything too new to me so Centos will be the platform.
The 2.5" drive I linked says it is 136MB/sec, so a single drive can keep up with network throughput. I want to run a couple of small VMs on there, so the quick seek speed of the 2.5" would be nice.
Of course, prices being what they are I see that 500MB drive has gone up £3 each since yesterday.