Are those SAS drives advertised as new ? I personally would not trust used (possibly heavily) drives for important storage .

EDIT: I searched for 4TB SAS drives in new condition on a certain auction site and they do seem a bit cheaper than NAS grade SATA drives .

Nope. I wouldn't be buying new SATA drives either, so it doesn't make any difference. Don't think I've bought a "new" HDD since the early 2000s.

Personally I'd trust ex-datacenter commercial drives over "home user" (subject to shoddy power management for years, banged around, cat hair choked, mouse wee-ed on, peanut butter smeared, and definitely not treated like a precision peice of equipment) drives if we're talking about second-hand stuff.

xjas wrote on 2020-05-04, 03:09:

Nope. I'm not buying new SATA drives either, so it doesn't make any difference. Don't think I've bought a "new" HDD since the early 2000s.

Well in that case, the only caveat I can think of is that used SAS drives will likely have seen 24/7 and heavier workloads than SATA drives used in a consumer setting . Then again, SAS drives are designed for heavier workloads .

Using used drives, you've never had multiple drive failures in RAID array cause DATA loss ?

EDIT: I agree that datacenter drives were probanly used in better condition than home used drives . That said, drives used in, for example, video streaming servers get used pretty heavily . Not sure I would want one of those. When you buy used, you don't know the drives's history . When you get it, you can always check SMART attributes, but you can't really do anything if you don't like what you see but the drive still works .

I recently bought a stack of 'cheap' used drives on fleabay. Here's the usage on one of them: Power on time: 2713 days; start/stop count: 18

If I were only buying one drive I'd be worried about it, but this won't be the only place I have really important stuff backed up & they'll be operating in RAID mirror anyway. I prefer cheap redundancy over shelling out for "new" when it's just not necessary. (And if I bought new drives, I could only afford the low end of the consumer stuff anyway.)

Basically what I'm asking here isn't, "should I buy used drives" *, it's "am I more likely to run into headaches with SAS + a controller card over SATA?" Things I'd be worried about with enterprise-type gear include:

- not being able to read the drives on a different SAS controller if the one I'm using fails
- forcing me into using a proprietary RAID format
- random BS incompatibilities / lack of support with free software (FreeNAS or some Linux-based solution)
- needing to hunt down barely-functional drivers from some Russian torrent site because I don't have a support contract
- cards not working on cheap consumer motherboards with absolutely no reason why
etc.

I've never messed with SAS stuff before, so advice is appreciated.

(* to put an end to that question, the choice is between me buying cheap used drives or not having a redundant backup system at all.)

xjas wrote on 2020-05-04, 04:42:

Basically what I'm asking here isn't, "should I buy used drives" *, it's "am I more likely to run into headaches with SAS + a controller card over SATA?" Things I'd be worried about with enterprise-type gear include:

- not being able to read the drives on a different SAS controller if the one I'm using fails
- forcing me into using a proprietary RAID format

Some SAS controllers only support RAID mode, where you must, at minimum define a single drive as a single volume JBOD array, or otherwise define an actual RAID array .
Some of the above (most LSI based, but not all) , controllers can be flashed to "IT mode" which allows direct drive access and drive transferability between controllers .
Driver support for a lot of the older, cheaper controllers is deprecated (possibly most/all ?) in certain Linux distributions which means continued support, even with workarounds, is uncertain .
Controllers mean to be used with internal drive bays are often fitted with an SFF-8087 connector and will require a specific cable to connect to said bay or breakout cable for individual SAS drives .

As long as you don't use RAID, they should be fine. RAID 1 should be fine as well since it just mirrors the drives.

Different controllers and all bets are off as far as different RAID modes go.

I've actually thought about getting a SAS controller and SAS drives as well but went SATA anyway for a couple more 4TB drives.

Just stay away from Seagate for sure. They are absolute crap even if SAS.

For SATA I go with HGST as I have had the best luck with them. WD is usually OK as well though I really dislike their Purple drives and I had a 320GB Blue that the platter itself warped and destroyed the drive. If you like to see platter coating confetti / metal flakes in a drive a warped platter is the way to go.

This is a topic that interests me as well. I'll soon be outgrowing my 2 TB hybrid drive and from the looks of it, used 8 GB SAS drives are surprisingly cheap. Which host controller would you go with? And if concerned about other systems not able to read your RAID array, wouldn't you just buy two of the same host/raid controllers for safe keeping?

They are cheap because no company would buy used drives, and hardly anyone else uses SAS drives. I would stay away from any kind of RAID though apart from plain old mirroring,p.

Just go with IBM M1015's or newer.. they can be flashed to IT mode for JBOD and software RAID type solutions. Also, SAS drives are usually more reliable since they're rated for a much better uncorrectable error rate. SATA is 10x more likely to encounter an error on the HDD controller versus a SAS controller. (10^14 vs 10^15 rate) Couple SAS with an ECC supported system and a file system / software with bit-rot protection (i.e. ZFS, BTRFS, SnapRAID) and you'll have a very reliable storage system. Really though, hardware RAID systems are losing ground, since software based solutions are offering better protection. For my file server, despite using SnapRAID, I still backup all ~30TB to Backblaze just in case my house burns down. 🤣

kolderman wrote on 2020-05-04, 11:24:

They are cheap because no company would buy used drives, and hardly anyone else uses SAS drives.

I rekon this is the reason. After supporting multiple Dell R710 servers with a pretty close 50/50 split between SAS and SATA cost for new SAS drives was always more.
I've only dealt with servers and their related SAS controllers abut never notices any limitations Most the time they actually supported both SAS and SATA drives (not in the same array)

I vaguely remember reading something that compared 2 similar spec SAS/SATA drives and it was just the interface that was different. So in away you are guaranteeing top binned drives.

I'll confirm most typical brand of failed drive was Seagate but it also represented 90% of drives under my control so the numbers were always going to be stacked.

Only downside I can really think is like SCSI its a dead end technology once drive supplies run out that controller is useless unless it can do SATA.

chinny22 wrote on 2020-05-05, 10:24:

Only downside I can really think is like SCSI its a dead end technology once drive supplies run out that controller is useless unless it can do SATA.

All SAS controllers support SATA natively, you can plug the drives in transparently.

Don't try doing it the other way around, your system really won't like it.. (Usually this isn't easily possible, but if you use an SAS hot swap bay that supports SATA inputs it's possible to attach SAS to SATA).

The downsides are more fiddly configuration, especially re-numbering of drives on OS bootup (I've learnt a fair bit about Linux initrds because of this), driver support fully stop, and it being fairly pointless unless high capacity or resilience are required.

chinny22 wrote on 2020-05-05, 10:24:

I rekon this is the reason. After supporting multiple Dell R710 servers with a pretty close 50/50 split between SAS and SATA co […]
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kolderman wrote on 2020-05-04, 11:24:

They are cheap because no company would buy used drives, and hardly anyone else uses SAS drives.

I rekon this is the reason. After supporting multiple Dell R710 servers with a pretty close 50/50 split between SAS and SATA cost for new SAS drives was always more.
I've only dealt with servers and their related SAS controllers abut never notices any limitations Most the time they actually supported both SAS and SATA drives (not in the same array)

I vaguely remember reading something that compared 2 similar spec SAS/SATA drives and it was just the interface that was different. So in away you are guaranteeing top binned drives.

I'll confirm most typical brand of failed drive was Seagate but it also represented 90% of drives under my control so the numbers were always going to be stacked.

Only downside I can really think is like SCSI its a dead end technology once drive supplies run out that controller is useless unless it can do SATA.

Though SATA compatible, SAS controllers such as the Dell H710 are pretty pick as to what SATA drives they like . Even with an unlocked BIOS (yes SAS controllers locked to drives from a specific OEM are a thing, the H710 used to be like that with early BIOSes), some drives keep registering errors even though they work fine on other controllers (I have a 1TB Seagate spinner and a 250GB HP SSD that are like that) .

Thanks for the advice all. Taking everything into consideration.

A seller local to me has some 3TB SATA drives for sale cheap, they were apparently Newegg "refurbs" that they personally didn't end up using. They were kind enough to get the SMART status for me:

I'm aware of the high power-on time, but honestly, some of the ones I'm backing up (which are primary data drives in PCs I use daily) are well higher than that. Again, money is super tight here, our dollar is low, and shipping to my island is usually a complete ripoff, so these have a BIG bonus of being local. I'm trying to do something on a shoestring that'll serve me for a couple years, not develop the perfect backup solution to last forever.

What strikes me as odd is that a lot of the stats are exactly the same - e.g. spin retry rate, seek error count, reallocated sector count, etc. I assume they all came out of the same RAID array, but even with that caveat, shouldn't these numbers vary a fair bit?

I would put them into RAID 1 and keep one drive as a spare, not RAID 5. Do you guys see any red flags here?

Just to ensure that whatever controller you use will work with 3 TB drives. I've had some RAID controllers only work up to 1 TB, but those were quite a bit older.

How much are the drives a piece? Talk him down based on lengthy up-times. Then ask about warranty.

feipoa wrote on 2020-05-23, 22:18:

Just to ensure that whatever controller you use will work with 3 TB drives. I've had some RAID controllers only work up to 1 TB, but those were quite a bit older.

How much are the drives a piece? Talk him down based on lengthy up-times. Then ask about warranty.

They'd be going on an LGA771 or AM2/AM3 board at the very earliest, so I wouldn't expect there'd be a compatibility issue there? I'd use software RAID with the onboard SATA ports (unless there's a good reason not to.)

The seller's asking $50 each and is firm, keep in mind I don't have to pay taxes + shipping on that. It's a private sale so I wouldn't expect a warranty.

Ya, you wouldn't think so, but I cannot say for sure. $50 each was what I figured.

Not sure if you're following all the stuff about SMR and SMR drives mis-labeled but that could be a factor in the pricing.