How "used" is a HDD with 25,000 hours but 25 power-on cycles?

[996GT2]

Bought a couple of "refurbished" (aka used) Hitachi Ultrastar 2TB enterprise drives from Newegg recently when they had a nice sale going on. When I got the drives, I ran them through HGST's extended drive test and all of the drives passed. None of the drives have any SMART errors.

The drives have around 25,000 power-on hours, but only 25 power-on cycles, which I presume means they were left on for extended periods of time, likely in a datacenter. My question is, is this kind of operation more "gentle" on a drive than the typical consumer usage, where a drive might have only 10,000 hours but 2,000 power-on cycles? (e.g. from restarting computer/putting computer in sleep mode).

My intention is to use these drives as backup drives. Would you consider them "safe" for this type of usage?

 

[dave_the_nerd]

Given the choice between a drive that was left on and hammered with I/O for three years, vs. a drive that was turned on and off several times a day for a shorter period of time, I don't know - I'd be suspicious of either one, but I'd expect them to exhibit different types of failures. (Bad blocks for the former, r/w head parking errors for the latter.)

Anyway, 25,000 hours is just shy of 3 years. On one hand, those drives have a 5 year warranty. On the other hand, I don't know how they were handled when they were retired from that datacenter, I don't know how they were packed, padded, treated, tested, etc., and I've definitely seen some crazy-high failure rates with enclosures full of drives that just took a "little bump" when they were being moved across a parking lot from data center A to data center B.

So as a matter of general principle, I'd not buy refurb'd drives. But if you got 'em and they work, well, use 'em.

 

[nerp]

Refurb drives are a risk, but you bought HGST drives which is the only refurb drive' I'd consider.

 

[jrichrds]

Not sure if I entirely trust power-on cycles count...at least what's reported by CrystalDiskInfo. I have a 5 year old drive I've turned on/off a lot of times, and I only get a power cycle count of 36.

 

[Yakk]

Those are most probably data center/server drives replaced on scheduled maintenance. These would preferably always be powered on and it's the luck of the draw if the data they contained was frequently accessed (like a SQL database) or just a backup or infrequently used drive.

Really it's just luck how long it will last IMO.

 

[bigboxes]

I wouldn't buy any used HDD. I run all my stuff 24/7 so I'd have similar numbers. And yes, I'd want drives that weren't turned off and powered up frequently. But I would just pass on used drives. It's bad enough that they give you refurbed drives for RMAs.

 

[VirtualLarry]

I'd rather have server pulls, if I was going to buy used drives, than any old random "refurb". At least, you know that they have been generally professionally taken care of (cooling, vibration, handling, etc.).

 

[Scarpozzi]

You really never know the operating temperature of the drives or how busy they were during those 25k hours. Journaling vs non-journaling file systems and the actual function of the server can make a huge difference in disk IO. If you saved money, just make sure you run RAID and/or backup your data and don't worry about it.

 

[tcsenter]

I've had pretty good luck with the "refurbed" drives (from reputable sellers/brands) but never put them into anything that requires 24/7 uptime, nothing mission critical.

 

[Mike64]

My intention is to use these drives as backup drives. Would you consider them "safe" for this type of usage?

"Backup" in which sense? As in, to have around in case you need a useable drive unexpectedly, or as in, to store backups on? Frankly, I wouldn't use them for the latter at all. Imo, it'd be far worse to discover that a "backup" had suddenly become unusable than to have an "in-service" drive (for which you have good backups) fail...

 

[billbillw]

FYI, those Hitachi were rated 1-million hours MTBF. I wouldn't worry. I have a pair of them myself, bought refurbed. Been using for more than a year in my NAS. Troublefree.

 

[dave_the_nerd]

FYI, those Hitachi were rated 1-million hours MTBF. I wouldn't worry. I have a pair of them myself, bought refurbed. Been using for more than a year in my NAS. Troublefree.

MTBF isn't really a super-helpful number on its own. (For instance, many consumer-level SSDs are rated at 1.2+ million hours MTBF, and nobody would seriously recommend using those in an data center situation.)

The AFR (annualized failure rate) is a more "real" number that's comprehensible by most people.

MTBF is useful as a relative indicator of reliability, if you're comparing apples to apples (for instance, 3.5" enterprise HDDs that are intended to work in given environment conditions, etc.) but even then, it's not actually indicative of how long a drive lasts - the average HDD isn't running for a million hours. (100+ years.)