Silverstone teases aluminium DS260 NAS chassis

[DanceswithUnix]

Given that, your suggested config sounds okay to me - although in my case it definitely IS about capacity. Or more specifically ... density ... I want as much storage as my wallet allows, in as small a space as possible.

I think performance and density is why corporate data centres are heading for 2.5in drives.

Sit some laptop drives next to 3.5in models, and you can see they are about a quarter of the volume. So in the space of a single 3.5in drive you can fit four 2.5in drives. Sticking to one manufacturer to try and keep things fair:

4TB = £133 http://www.scan.co.uk/products/4tb-h...-cache-8ms-ncq
4x1TB = £200 http://www.scan.co.uk/products/1tb-h...0rpm-8mb-cache

So there is a hefty price penalty for us, but in enterprise drives I expect the gap will close a lot. So what would 2.5in drives get you? Each drive can peak 115MB/sec for a total 460MB/sec reading all at once dipping to an aggregate 200MB/sec reading all from their lowest point. If one drive fails, it doesn't take as long to rebuild an array of 1TB drives as it does an array of 4TB drives.

If you want to use 2TB WD Green 2.5in drives, then in the volume of a single 3.5in drive you can get 8TB!

So as I said, I think for home use a small number of 3.5in drives still has a meaningful cost advantage, but you are already losing performance and density by going with big drives. The cost advantage will decrease over time, and then 3.5in drives will disappear.

[herulach]

I think performance and density is why corporate data centres are heading for 2.5in drives.

Sit some laptop drives next to 3.5in models, and you can see they are about a quarter of the volume. So in the space of a single 3.5in drive you can fit four 2.5in drives. Sticking to one manufacturer to try and keep things fair:

4TB = £133 http://www.scan.co.uk/products/4tb-h...-cache-8ms-ncq
4x1TB = £200 http://www.scan.co.uk/products/1tb-h...0rpm-8mb-cache

So there is a hefty price penalty for us, but in enterprise drives I expect the gap will close a lot. So what would 2.5in drives get you? Each drive can peak 115MB/sec for a total 460MB/sec reading all at once dipping to an aggregate 200MB/sec reading all from their lowest point. If one drive fails, it doesn't take as long to rebuild an array of 1TB drives as it does an array of 4TB drives.

If you want to use 2TB WD Green 2.5in drives, then in the volume of a single 3.5in drive you can get 8TB!

So as I said, I think for home use a small number of 3.5in drives still has a meaningful cost advantage, but you are already losing performance and density by going with big drives. The cost advantage will decrease over time, and then 3.5in drives will disappear.

Its about reliability and useage models as much as anything else at the moment though - most datacentres won't be space constrained (except for stuff that is by neccessity close to financial centres etc). I'm sure people much smarter than me have worked out the relative efficiency/reliability of say 4*1tb disks in RAID 5 vs a single 3TB. I suspect a lot will depend on the access profile of the data as much as anything else.

Until platter density gets up into the 4TB in a 2.5" drive range I can't see me using them, but then I typically have 4 machines great grandfathered, plus a big music/video library etc and of course (like the majority of home users) Upfront cost is a much bigger factor than TCO.

[DanceswithUnix]

I think you are right that the cost has some way to come down for this stuff to get interesting for consumer use.

OTOH, the cheapest drives available right now are 2.5in models with plenty around under £35. For £70 and in less space than a single 3.5in drive you can have a pair of 500GB drives in a raid 1 mirror. Just about everyone I know can happily live in 500GB for their main drive, for them the improved reliability of raid 1 could be pretty nice for the small increase in money.

I am still struggling to come up with a use for six 2.5in drives in a consumer setting though. That gets you a 4+2 raid 6 setup which would be really low risk if that is important to you, but also a lot of faff for only 4TB

[crossy]

I think you are right that the cost has some way to come down for this stuff to get interesting for consumer use.

Got to happen though - "enterprise" prove the technology and make it cheaper and then it gets trickled down. That seems to have been the case in the past, (e.g. SSD's), and I can't see a reason for it to change.

OTOH, the cheapest drives available right now are 2.5in models with plenty around under £35. For £70 and in less space than a single 3.5in drive you can have a pair of 500GB drives in a raid 1 mirror. Just about everyone I know can happily live in 500GB for their main drive, for them the improved reliability of raid 1 could be pretty nice for the small increase in money.

Funnily enough that's exactly what I've done - got a Silverstone DS221 bought from Scan ages ago.

This has a pair of 500GB WD Blue's in RAID1 connected via eSATA. I use it to hold my Virtual Machine "lab" and it's proven fast enough to cope - best of all it's more or less silent. Setup was laughably easy and the only real downside is that the PSU they supply is equipped with US/shaver style two pins, so I needed an adaptor.
(By the way, the image I've shown is the DS221 in it's stand - without that stand it is, as you say, about the same volume as a 3.5" drive)

I am still struggling to come up with a use for six 2.5in drives in a consumer setting though. That gets you a 4+2 raid 6 setup which would be really low risk if that is important to you, but also a lot of faff for only 4TB

Good point about the raid 6 setup - think I'd go for a 5+1 RAID5 deal and accept that single point of redundancy in return for a fragment of extra space.

By the way, I sent you and Herulach a thanks each - been an interesting discussion.

[crossy]

Actually here's a question I'm going to have to research - Silverstone say that this supports SSD's and 2.5" HDD's. But do they support the older/larger 9.5mm high 2.5" HDD's or, as I strongly suspect, it's 7mm high drives only?

Just took a quick scan @Scan at 1TB WD Blue drives. They've got two - WD10JPVX and WD10SPCX at costs of £53 and £92 respectively. The only differences are that the cheaper drive is 9.5mm v's 7mm and 8MB v's 16MB. So if this enclosure supported the older drives then surely there's some substantial savings to be had by using the older drives. And I can't see that 8MB of cache shortfall making much of a difference in speed in a RAID array.