Question re SAS on Poweredge 2950

ajf · 29 Oct 2009 at 13:08

We have a Dell Poweredge 2950 which has 6 SAS disk bays.
Am I correct in understanding these support standard SATA disks?

Two bays are currently populated with 2x 146Gb 15k SAS Cheetah
The other 4 are 500Gb 7.2k SAS Barracuda
We want to replace these 4 with 1Tb disks but as far as I can see there are no SAS disks that big.

I am not overly familiar with SAS so please advise!

Many thanks
Andrew

iaind · 29 Oct 2009 at 13:11

The 500gb disks wont be true SAS - they're probably what Dell call Nearline-SAS, which are SATA disks with a SAS interface.

I'm sure SATA will work fine, but you'll want Dell disks for support reasons.

madman045 · 29 Oct 2009 at 15:20

If they are hotswappable then you will definately want the kit from Dell as they will connect to a backplane.

1TB isnt cheap mind you, http://accessories.euro.dell.com/sna/productdetail.aspx?c=uk&l=en&cs=ukdhs1&sku=400-16111

ajf · 29 Oct 2009 at 15:27

Thanks.
Yeah our supplier just came back with the response about the hot swap issue.
Slightly less eye watering at £310 ex vat per disk, but still...
I assume the connectors are aligned differently?
Why couldn't they just make it nice and simple!!

Andrew

iaind · 29 Oct 2009 at 15:44

Nope, SAS and SATA have identical connectors in standard alignment

Saundie · 29 Oct 2009 at 17:23

If you're not too worried about the warranty implications, it's easy enough to remove the SAS interposer on the back of the drives, take the drives out of the caddies and replace them with off the shelf 1TB drives for £70 a go.

You would need to check to ensure that your drives have the interposer before you do this, as I cannot recall if all the drives use it. It is the bridge/adapter thing at the back of the drive, and looks like this:

Of course, this is not going to be supported by Dell, but it is nice to have the option, I suppose.

ajf · 29 Oct 2009 at 18:36

As far as I could see this is not used.
The drives look the same as this one:
http://compeve.com/images/ST3300555SS.jpg
Which is then screwed into a 3 sided hot swap caddy.
There appear to be no additional interfaces between the drive and the backplane so I could not see a problem with using the standard SATA drives as you suggest.
Speed is not an issue - the 500Gb are only 7.2k anyway!

We already have the hot swap caddies from the current drives.

Saundie · 29 Oct 2009 at 19:25

In which case, there's no technical reason why you cannot remove the drive from the caddy and replace it with a larger one - I did this with the 80GB drives I got with my PowerEdge 2950, replacing them with 500GB drives. I am not sure how this would affect your warranty, though.

Sin_Chase · 29 Oct 2009 at 20:22

I would assume it will void the warranty on the caddys (obviously) and may or may not have implications for the backplane.

Saundie · 29 Oct 2009 at 22:27

That is what I am unsure of - I didn't want to ask my Dell account manager, as it would have been a dead giveaway that I'd changed the hardware!