Does Time Capsule Contain Server-Grade Drives? I’d Say Yes.

It seems the minute Time Capsule began shipping some were quick to find fault with a claim made for the device. I guess when Steve Jobs used a fairly vague description like “server-grade” to describe the hard drive, such fault can always be found.

The problem for doubters is that the vagueness works both ways. Establishing a definition for “server-grade” based on a Google search, and then claiming Apple didn’t meet it, is easy but hardly conclusive.

Here’s my take on it. I’ll look at the drive in my iMac as an example of a “regular” hard drive, and then look at the 500GB and 1TB drives identified in Time Capsules so far.

iMac 2.8GHz Extreme (750GB)

Drive: Seagate 3750640AS

Marketing spiel: “Barracuda 7200.10 hard drives deliver superb performance, efficiency, speed and durability for all your application needs.”

MTBF: 700,000 hours

Unrecoverable errors: not listed

From the marketing talk it seems clear this is designed as a high-capacity general performer.

Time Capsule 500GB

Drive: Seagate 3500630NS

Marketing spiel: The Seagate® Barracuda® ES enterprise hard drive is the industry’s most reliable, highest capacity 7200-RPM hard drive for 24 x 7, multidrive, business-critical applications.

MTBF: 1,200,000 hours

Unrecoverable errors: 1 in 10^14

Well, their marketing group would say it’s the “industry’s most reliable”, which of course is questionable, but the point is they’re claiming 24/7, business-critical apps. Clearly this drive is a step up from the more general purpose one in my iMac.

While I cannot compare the error rate between the drives, the MTBF speaks volumes (pun intended), with a figure over 70% higher than the drive in the iMac.

Time Capsule 1TB

Drive: Hitachi DeskStar 721010KLA330

Marketing spiel: Suggested Applications: Internal and external storage for consumer computers * Networked storage servers * Extreme gaming machines * Video editing arrays

MTBF: not listed

Unrecoverable errors: 1 per 1.0 E15 bits transferred

While the first suggested application applies to every drive ever built, I’d say the second one (and even the final two) imply more rugged duty than the average desktop drive. Further, if you go to Compare Hitachi Products and select this drive you’ll see one Application listed is “Entry server” — I consider the Time Capsule a very “entry server”.

As for stats, there’s no MTBF listed, but the unrecoverable errors compare favorably to the second Seagate.

It should also be noted that this drive is the current “jewel” in the DeskStar line, and the only 1TB model. There is a higher series of Hitachi drives (Ultrastar), but the application listed on comparison is “Enterprise server”. A bit overkill, and I’d say the expense (remember we’re talking about a 1TB drive) simply didn’t make it cost-effective for TC’s primary purpose. After all, Apple didn’t state they’d use the “best” server-grade drive money could buy.

For those interested, here’s a review I found on the TC’s Hitachi drive. They give it a 9 out of 10 and Editors Choice.

Finally, Apple responded to the above article questioning the server-grade drives, saying:

[Senior product manager Jai] Chulani clarified that the “server-grade” drives in a Time Capsule are the same 7200 rpm drives used for Apple’s Xserve servers, and that they have a higher mean time between failure (MTBF) rating than consumer drives. The MTBF for server-grade drives is often 1 million hours (114 years), which is a measure of probability; in this case, that out of a set of drives with similar properties, an extremely high percentage will still be fully functional after several years.

This makes perfect sense to me, and the fact that these are the drives Apple uses for their Xserves shows they put their money where their mouth is.

I believe these drives are, by any reasonable definition, server-grade as used in a consumer server like Time Capsule.

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4 thoughts on “Does Time Capsule Contain Server-Grade Drives? I’d Say Yes.

  1. The drives may be server grade, but the rest of the system is definitely not. Power supply failures are occurring at an alarming rate at around 18 months, according to Mac support forums. There is even talk of a class-action lawsuit.

  2. There were test done by google (and others) not so long ago that showed that the failure rate between desktop drives vs. enterprise drives didn’t equate to good value for money. (I think it was 5-6%)

    Also a different report showed that 10,000 drives were on average not much faster that 7,200 rpm drives.

    Google uses good quality desktop drives in all their servers.

  3. If you go here you can see that Apple’s criteria was based off the higher mean time between failure. Re-reading that though, they didn’t mention the exact MTBF for the exact model they’re using, they just vaguely pointed out that usually server grades MTBF rating is about a million hours or 114 years.

    Sebastian

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