Server hard drives: what to check on interface and bay before buying

Which server hard drive fits? Four checks before any price

A server hard drive is only cheap if the server can use it, so the order of work here is the reverse of a price list. Settle these four points on the machine first, and only then open a table.

• Controller. Find out whether the drive will sit on a SAS or a SATA controller. That decides which rows are open to you.
• Bay size. The tables are split by 3.5-inch and 2.5-inch because the drive has to suit the bay. We have no document on fitting a smaller drive into a larger bay, so we make no claim about it.
• Caddy or tray. We hold no vendor document on caddies or trays. Confirm with the server's maker what the bay needs before you order.
• The server's own documents. Only the server maker's list can say a named part number is supported. No row on this page is a claim that a drive suits a given machine.

The controller check has a firm answer, from Seagate's support note. It works in one direction only:

3.5-inch SAS server hard drives

If the controller is SAS, these rows are open to you. There are 48 enterprise listings in this table, lowest price first, and the lowest is £89.99 inc VAT. New and used sit together, so read the Condition column on every row.

Part numbers matter more than range names here. Toshiba makes the MG series in 6 Gbit/s SATA and dual-port 12 Gbit/s SAS versions, and aims it at enterprise storage arrays and industrial servers. Seagate lists the Exos 7E10 as separate SATA and SAS models, with names as specific as 'Exos 7E10 10 TB 4Kn SAS', so two drives of the same capacity and interface are not always the same model. A listing whose interface we could not read is not in this table, so it can undercount. SAS hard drives go further on this class.

3.5-inch SATA server hard drives

SATA is the side of Seagate's rule with more room. A SATA drive may be plugged into a SAS controller as well as a SATA one, so on interface alone it is open to either kind of machine.

This table lists 71 enterprise SATA listings, from £89.99, again with both conditions together.

How hard the machine will work matters too. Toshiba rates the MG series for 24/7 operation at 550 TB/year, which gives you one concrete figure to hold your own workload against. It belongs to that series alone, and we do not extend it to the other rows. Best server hard drives and SATA enterprise hard drives narrow the field in other ways.

2.5-inch SAS drives for smaller bays

Machines with 2.5-inch bays have this separate list, SAS only: 29 listings, from £41.08. Unlike the two tables above, it is not filtered by product class, because the filter here is the interface and the size. We do not table 2.5-inch SATA enterprise drives on this page.

Server hard drive price and deals: how to read these tables

All three tables run by price, lowest first, so the outlay for one drive is plain at a glance. That order favours small drives, and a low price at the top may buy far less capacity than the row beneath it. The £/TB column is there to correct for that, and price per TB ranks on that measure alone.

We do not mark any row as a deal. The tables show what each listing asks now, with no earlier price beside it, so they cannot tell you that a figure is a discount. If you are hunting server hard drive deals, the honest use of these tables is to find the lowest current price for the exact part number your machine needs, and to weigh a saving against the condition and warranty on the listing. Cheap enterprise hard drives takes the budget angle.

Used server hard drives: buying second hand on Amazon.co.uk

Server hard drives refurbished or second hand appear in the same tables, marked Used in the Condition column. The label does not say how the drive was prepared, what it has done, or who stands behind it, and our tables hold no hours-run figure. That leaves the listing to answer:

• Seller: who is selling it, because that is who any claim goes to. The name appears under the condition where Amazon.co.uk gives one.
• Wording: whether the listing calls the drive refurbished, recertified or simply used, and who did the work.
• Warranty: the length, and who provides it. Do not assume a maker's term for a new drive carries across.
• Part number and interface: the same checks as a new drive. An n/s in the table means we could not read that value from the listing.
• History: ask what the drive has done. A rating such as Toshiba's describes a series, not this unit's past.

On warranty, Seagate gives a clear example: its recertified drives carry a six-month warranty, and the new-drive term does not follow them. We cannot tell from a Used row whether a drive belongs to that programme. Used server hard drives and refurbished SAS drives concentrate on this part of the market.

Your statutory rights as a consumer run against a trader seller. For a fault, the where-to-buy guide sets out the time limits Which? gives. For an online order you no longer want, Which? says you can cancel up to 14 days after receiving the goods, with return postage falling to you unless the retailer says it will pay.

Three limits on that. Which? is describing consumer rights, and we hold no source on purchases made by a business. We have not found a source that deals with second-hand drives specifically. And we have not read Amazon.co.uk's own returns terms, so we state none of them: check them on Amazon.co.uk before you order.