Dell PowerEdge R740 drives: three front bay layouts, Dell's drive list and UK prices

Dell R740 drive bays: the three front backplanes

Dell's technical guide gives the R740 three front backplane configurations: 8 x 2.5-inch, 8 x 3.5-inch and 16 x 2.5-inch drives. All three are front-accessible and hot-plug, and the guide states plainly that the R740 has no rear or mid-bay storage options. Whatever you buy goes in at the front.

Divide each maximum by its bay count and the two line up with Dell's drive list. 128TB across eight bays is 16TB a bay, the top 3.5-inch SATA size on the list. 122.88TB across sixteen bays is 7.68TB a bay, the top 2.5-inch SAS SSD size on the list. Both divisions are our arithmetic; the guide prints the totals, not a per-drive figure.

For the smallest layout, 8 x 2.5-inch, we have not found a maximum from Dell, so we print none. On NVMe, we have not found a statement in Dell's guide that the base R740 has NVMe front bays, and we make no claim that it does.

R740 or R740xd: which chassis do you have?

The two machines share a guide and a drive list, which is why they are so often confused. Dell gives the R740xd up to 12 x 3.5-inch or 24 x 2.5-inch front drives, plus a 4 x 3.5-inch mid-bay option that also takes 2.5-inch drives in the Hybrid carrier. None of that exists on the R740.

• Twelve 3.5-inch or twenty-four 2.5-inch bays at the front: an R740xd. Dell's R740 figures stop at eight and sixteen.
• Any drive bay behind the front panel, mid or rear: an R740xd.
• Eight 3.5-inch, or eight or sixteen 2.5-inch, at the front and nothing else: an R740.

The difference is in how many bays there are and where they sit, not in which drives Dell lists, because the drive tables below cover both machines. Dell's later PowerEdge generations are compared on Dell PowerEdge hard drives.

PowerEdge R740 drives Dell lists: SATA to 16TB, SAS to 10TB

The line to remember for 3.5-inch bays is SAS. Above 10TB, Dell's list offers SATA only, so a 12TB, 14TB or 16TB drive for an eight-bay R740 is a SATA drive if you want to stay on it. Dell's guide is Rev. A09 of December 2021, so these are the sizes Dell offered as of that guide. A drive above a line is not on the list, and we have not found a document that states how an R740 treats one.

3.5-inch SAS drives for the 8-bay R740

These are maker-branded 3.5-inch enterprise SAS drives, not Dell-labelled kits, lowest £/TB first. The table shows 8 listings right now. Lowest £/TB at the last check: £30.00/TB. All prices are pounds sterling inc VAT on Amazon.co.uk.

The table is not capped at Dell's 10TB SAS line, so rows above it can appear. Use the capacity column first. New and used rows share the table; the Condition column says which.

3.5-inch SATA drives for the 8-bay R740

SATA is where Dell's 3.5-inch list goes furthest on this server, to 16TB. Eight bays at that size is the 128TB maximum in Dell's specification table. The table shows 8 listings right now. Lowest £/TB at the last check: £20.49/TB.

As with SAS, the table runs beyond Dell's printed sizes. For a mixed array, or a SAS drive alongside SATA ones, check the controller's documentation; SAS vs SATA covers the two interfaces in general.

2.5-inch drives for the 8 and 16-bay R740

The two 2.5-inch layouts take hard drives or SSDs. On Dell's list the largest 2.5-inch hard drive is 2.4TB, on the SAS 10K line; 15K drives stop at 900GB and the 7.2K lines at 2TB. The 2.5-inch SAS SSD line reaches 7.68TB and the SATA SSD line 3840GB, so for capacity in sixteen small bays the SSD rows are the ones to compare. The tables below cover 2.5-inch SAS hard drives, then 2.5-inch SATA and SAS SSDs.

For a 2.5-inch hard drive, check the spindle speed on the maker's sheet and hold the capacity against the matching line above. The SAS SSD table holds 2 listings right now. Dell's 2.5-inch SAS SSD line reaches 7.68TB, so check each row's capacity against it; the SSD sizes are set out by generation on Dell PowerEdge SSD. Dell also notes that 15k hard drives generate more acoustic noise than lower-speed drives, and that noise increases with the number of hard drives.

Storage controllers Dell lists for the R740

The guide's list of internal storage controller cards is: H330 and H350, both marked R740 only, then H730P, H740P, H750, HBA350i, HBA330 and S140. Before ordering drives, find out which card your server carries, because it is the part that talks to the disks. We have not found a per-card drive list from Dell, so the card's own documentation is the place to confirm anything beyond interface and size.

With eight 3.5-inch bays, the RAID level decides how much of the raw capacity you keep. The calculator below works it out for your drive size and count.