Help me choosing a DAS for my backups and media storage :-)

[drsox]

And what about those recommendations on not using desktop-class drives on a RAID?

Here's a BIG study done on why desktop-class drives are good enough for use as backup/RAID drives. : http://blog.backblaze.com/2013/11/12/how-long-do-disk-drives-last/

I've used desktop-class drives in RAID units for the last 7 years or so and never (touch wood) had a drive problem that was not able to be managed using a replace/rebuild approach. I also have a backup RAID unit so I can manage any problems caused by failure in the RAID unit itself - something to consider ?

 

[matreya]

I've used desktop-class drives in RAID units for the last 7 years or so and never (touch wood) had a drive problem that was not able to be managed using a replace/rebuild approach. I also have a backup RAID unit so I can manage any problems caused by failure in the RAID unit itself - something to consider ?

The desktop-class drives I've been using in various RAID units have been Hitachi (HGST) Deskstars & Toshiba DT01ACA200s. Out of 19 drives in 2TB and 3TB sizes, I've only had 1 drive fail RAID (and subsequently used as a regular hard drive without issue).

The most recent incarnation of Hitachi deskstars are in the form of Toshiba DT01ACA100,200 & 300 drives (WD had to offsell some of it's Hitachi assets to Toshiba), and HGST (now part of WD) Deskstar NAS drives.

 

[drsox]

The desktop-class drives I've been using in various RAID units have been Hitachi (HGST) Deskstars & Toshiba DT01ACA200s. Out of 19 drives in 2TB and 3TB sizes, I've only had 1 drive fail RAID (and subsequently used as a regular hard drive without issue).

The most recent incarnation of Hitachi deskstars are in the form of Toshiba DT01ACA100,200 & 300 drives (WD had to offsell some of it's Hitachi assets to Toshiba), and HGST (now part of WD) Deskstar NAS drives.

Yes, good drives but a bit noisy if used outside a RAID setup (it doesn't matter much about the noise in a RAID setup !). I had 12 1TB Samsung drives and 4 failed - absolutely the pits for RAID but they were the quietest for normal use. The other BAD drives I had were 1.5TB Seagates - I RMA'd most of them and then sold off the replacements. Now I have 11 3TB Seagates, so far so good, no SMART errors of any kind last time I checked.

 

[matreya]

Yes, good drives but a bit noisy if used outside a RAID setup (it doesn't matter much about the noise in a RAID setup !).

Actually, the HGST Deskstar NAS drives I bought a week ago are a good deal quieter than the regular Deskstar drives I bought a year ago (all 3TB in size).

 

[drsox]

Actually, the HGST Deskstar NAS drives I bought a week ago are a good deal quieter than the regular Deskstar drives I bought a year ago (all 3TB in size).

Nice to know, cheers.

 

[iRock1]

Help me choosing a DAS for my backups and media storage

You can get a theoretical maximum transfer rate of 60MB/sec with USB 2.0, and only 100MB/sec with FireWire 800. In real life, you aren't going to see those rates however, depending on the drives themselves.

I know the differences between theoretical and "real life" speeds, but I wouldn't have expected such a low difference between USB and FW. Only 10 MB/s using 5400 rpm disks in both cases? I tend to think that the low performance has something to do with the Red drive itself rather than the interface.

I also have a backup RAID unit so I can manage any problems caused by failure in the RAID unit itself - something to consider ?

Do you mean a second independent RAID working as a backup of the main one? I want to do something like that in the future. Probably it will be an off-site NAS, but definitely something more like in the mid/long-term. By now a single RAID with redundancy will be enough.

Now, in a hypothetical future scenario like the one describe, I don't know if redundancy in the main RAID will be necessary having an offsite backup.

 

[drsox]

Do you mean a second independent RAID working as a backup of the main one? I want to do something like that in the future. Probably it will be an off-site NAS, but definitely something more like in the mid/long-term. By now a single RAID with redundancy will be enough.

Yes, a duplicate unit that I fire up every week and update as a mirror. I also have a UPS on each unit. The one aspect I can't control seems to be digital data rot ! Some of my long term audio files have started to get slight corruptions (small sections that no longer play or play with screech etc noise). Unfortunately these errors have mirrored over to the backup also. I do data scrubbing and error checking every so often but not often enough it seems. Usually I just delete the file and re-rip if it's one I really want.

 

[iRock1]

Yes, a duplicate unit that I fire up every week and update as a mirror. I also have a UPS on each unit. The one aspect I can't control seems to be digital data rot ! Some of my long term audio files have started to get slight corruptions (small sections that no longer play or play with screech etc noise). Unfortunately these errors have mirrored over to the backup also. I do data scrubbing and error checking every so often but not often enough it seems. Usually I just delete the file and re-rip if it's one I really want.

I'm far from being an expert, but for what I've seen in this same forum, if you limit yourself to mirror the contents of your main RAID to the backup system, the latest is not a real backup. You should "archive" your contents in the second RAID, so if a file gets corrupted in the future you can still retrieve an older version of it.

Now, all of this is pure abstraction to me. Honestly, I'll be doing just fine with a RAID 5 and the standard protections against digital corruption, and even the idea of having an additional RAID seems like an overkill to me.

 

[drsox]

I'm far from being an expert, but for what I've seen in this same forum, if you limit yourself to mirror the contents of your main RAID to the backup system, the latest is not a real backup. You should "archive" your contents in the second RAID, so if a file gets corrupted in the future you can still retrieve an older version of it.

Now, all of this is pure abstraction to me. Honestly, I'll be doing just fine with a RAID 5 and the standard protections against digital corruption, and even the idea of having an additional RAID seems like an overkill to me.

Yes, fine but what do you do if you change/update some of the contents of your active files. This is what TM is supposed to do, but how far back do you need to go to retrieve the unadulterated version of a file that was changed by some random event that you don't know when occurred. Good luck trying to remember when you last changed/updated a file vs a random corruption.

For the home user I don't think this matters wrt audio/video files. Personal data such as info and pics, well that's something else. Not sure I have the answer to this, that's why I still make paper copies of stuff that is really critical (bank accounts, tax data, immigration status etc etc)

 

[iRock1]

Getting on-topic again... Could you people recommend me more enclosures, please?

 

[iRock1]

Ok, after a lot of research I'll go with the Mobius. Sadly there won't be stock for the next 2-3 weeks.

 

[thekev]

And what about those recommendations on not using desktop-class drives on a RAID?

I'm far from being an expert, but for what I've seen in this same forum, if you limit yourself to mirror the contents of your main RAID to the backup system, the latest is not a real backup. You should "archive" your contents in the second RAID, so if a file gets corrupted in the future you can still retrieve an older version of it.

Now, all of this is pure abstraction to me. Honestly, I'll be doing just fine with a RAID 5 and the standard protections against digital corruption, and even the idea of having an additional RAID seems like an overkill to me.

Many of the problems mentioned with the non-enterprise type specifically refer to issues with parity based raids such as raid 5. A raid 5 can crash on a rebuild if one bit is off in the entire raid, so I wouldn't stack your entire backup hopes on it. You seem a bit misguided on the protections that are available.

 

[matreya]

Many of the problems mentioned with the non-enterprise type specifically refer to issues with parity based raids such as raid 5. A raid 5 can crash on a rebuild if one bit is off in the entire raid, so I wouldn't stack your entire backup hopes on it. You seem a bit misguided on the protections that are available.

He'll learn when his only copy of important data is lost, because he didn't do a proper backup of a RAID array..

I've only had to a RAID5 array rebuild itself once (using Hitachi Deskstars), but I had a complete backup of its contents all the same.

And even if the hard drives are perfect, if the RAID enclosure itself fails one day (and that's happened to me TWICE, 1st with a Qx2 that just up and died, and the 2nd when another set of RAID5'd drives would keep dropping out about once a day, in another Qx2)

All the drives are still working perfectly fine in new enclosures though, but if I didn't have backups on hand, I would have lost about 6TB of data.

 

[hfg]

He'll learn when his only copy of important data is lost, because he didn't do a proper backup of a RAID array..

I've only had to a RAID5 array rebuild itself once (using Hitachi Deskstars), but I had a complete backup of its contents all the same.

And even if the hard drives are perfect, if the RAID enclosure itself fails one day (and that's happened to me TWICE, 1st with a Qx2 that just up and died, and the 2nd when another set of RAID5'd drives would keep dropping out about once a day, in another Qx2)

All the drives are still working perfectly fine in new enclosures though, but if I didn't have backups on hand, I would have lost about 6TB of data.

What RAID enclosures are you now using?

 

[thekev]

He'll learn when his only copy of important data is lost, because he didn't do a proper backup of a RAID array..

I've only had to a RAID5 array rebuild itself once (using Hitachi Deskstars), but I had a complete backup of its contents all the same.

And even if the hard drives are perfect, if the RAID enclosure itself fails one day (and that's happened to me TWICE, 1st with a Qx2 that just up and died, and the 2nd when another set of RAID5'd drives would keep dropping out about once a day, in another Qx2)

All the drives are still working perfectly fine in new enclosures though, but if I didn't have backups on hand, I would have lost about 6TB of data.

As you point out controller failure can happen. There are issues with using typical desktop drives in raid 5. Their error recovery timings are different and can cause the drive to time out. If the lack of backup an issue of budget, a costly raid may not be the best idea. I don't even know what he means about standard protections. I think there is a certain amount of implicit assumption there, just like people assume their ssds will never fail due to lack of mechanical parts.

And even if the hard drives are perfect, if the RAID enclosure itself fails one day (and that's happened to me TWICE, 1st with a Qx2 that just up and died, and the 2nd when another set of RAID5'd drives would keep dropping out about once a day, in another Qx2)

All the drives are still working perfectly fine in new enclosures though, but if I didn't have backups on hand, I would have lost about 6TB of data.

You know that could be an issue of drives attempting error recovery. The thing about enterprise drives is that they will not attempt to do so as long as the consumer ones, thus preventing a timeout in a multiple drive configuration

 

[matreya]

You know that could be an issue of drives attempting error recovery. The thing about enterprise drives is that they will not attempt to do so as long as the consumer ones, thus preventing a timeout in a multiple drive configuration

That would have been a consideration except placing the exact same desktop drives into a new Qx2 worked perfectly for months, before I upgraded the size of the RAID with new HGST Deskstar NAS drives.

 

[thekev]

That would have been a consideration except placing the exact same desktop drives into a new Qx2 worked perfectly for months, before I upgraded the size of the RAID with new HGST Deskstar NAS drives.

Interesting.. could have been a flakey controller. I wouldn't trust the low end ones with Raid 5. Typically ECC cache memory is a necessity there due to the nature of rebuilding a Raid that relies on parity to reconstruct data.

 

[matreya]

Interesting.. could have been a flakey controller. I wouldn't trust the low end ones with Raid 5. Typically ECC cache memory is a necessity there due to the nature of rebuilding a Raid that relies on parity to reconstruct data.

I'm considering replacing the Qx2 with a Promise2 R4 (diskless) from the Apple Store...

 

[iRock1]

Many of the problems mentioned with the non-enterprise type specifically refer to issues with parity based raids such as raid 5. A raid 5 can crash on a rebuild if one bit is off in the entire raid, so I wouldn't stack your entire backup hopes on it. You seem a bit misguided on the protections that are available.

I plan to use WD Red. I hope that minimizes the chances of getting a disaster.

If the lack of backup an issue of budget, a costly raid may not be the best idea.

What would you recommend me then?

 

[matreya]

I plan to use WD Red. I hope that minimizes the chances of getting a disaster.

LOL, I tried the WD Reds in a RAID5, I wouldn't touch them again with a barge pole... toshibas and HGST perform better.

 

[iRock1]

LOL, I tried the WD Reds in a RAID5, I wouldn't touch them again with a barge pole... toshibas and HGST perform better.

Could you explain yourself more clearly?

 

[matreya]

Firstly, the WD Reds in RAID 5 were much slower than HGST Deskstar NAS drives I replaced the Reds with. We're talking 100MB/sec vs 250MB/sec.

Secondly, one of the WD Red 2TB drives started failing after a few months of being redeployed in a RAID 1 enclosure for time machine backups.

 

[thekev]

What would you recommend me then?

Well Raid is never going to be cheap. You could go with two separate DAS setups, one being storage and the second being backup. Drives can be stored as individual volumes. You can take a risk with raid if you like, but first why not familiarize yourself with the cost of attempted data extraction on a raid if it does crash and you actually need something. You're talking insurance claim at that point. It's also possible to avoid Raid 5 configurations. They're just finicky and somewhat hardware dependent.

 

[iRock1]

Firstly, the WD Reds in RAID 5 were much slower than HGST Deskstar NAS drives I replaced the Reds with. We're talking 100MB/sec vs 250MB/sec.



Secondly, one of the WD Red 2TB drives started failing after a few months of being redeployed in a RAID 1 enclosure for time machine backups.

Certainly WD Reds are slower, since they spin at 5400 RPM. However, and as I stated before, I pretend to implement this through FireWire 800. Assuming this, the difference between enterprise class drives and WD Reds, in terms of speed, is nonexistent.

Now, when it comes to personal experiences with drives, we all have had problems with any brand. That doesn't mean a particular brand or model is bad (unless there are too many reviews and tests claiming the opposite).

Well Raid is never going to be cheap. You could go with two separate DAS setups, one being storage and the second being backup. Drives can be stored as individual volumes. You can take a risk with raid if you like, but first why not familiarize yourself with the cost of attempted data extraction on a raid if it does crash and you actually need something. You're talking insurance claim at that point. It's also possible to avoid Raid 5 configurations. They're just finicky and somewhat hardware dependent.

I'm sold to the idea of using a single enclosure because it means less junk. I hate having multiple drives and stuff in general sitting around on my desk (as I've been doing until now). On the other hand, it's always more comfortable to work with just one or two partitions instead of one for each drive.

Do you have better recommendations than RAID 5 and JBOD?

 

[marzer]

Certainly WD Reds are slower, since they spin at 5400 RPM. However, and as I stated before, I pretend to implement this through FireWire 800. Assuming this, the difference between enterprise class drives and WD Reds, in terms of speed, is nonexistent.

Now, when it comes to personal experiences with drives, we all have had problems with any brand. That doesn't mean a particular brand or model is bad (unless there are too many reviews and tests claiming the opposite).





I'm sold to the idea of using a single enclosure because it means less junk. I hate having multiple drives and stuff in general sitting around on my desk (as I've been doing until now). On the other hand, it's always more comfortable to work with just one or two partitions instead of one for each drive.

Do you have better recommendations than RAID 5 and JBOD?

Whew, this thread has come full circle

For a home setup, I fall back to my earlier recommendation for a four drive setup. Two drives configured in RAID1 as your primary storage set, 2 drives in RAID0 as the backup data set. I've operated my media library this way for years. If a drive in the primary set goes out you can continue to operate until you get around to rebuilding the mirrored set.

Since you want a single enclosure, take a look at http://eshop.macsales.com/item/OWC/M3QX2KIT0GB/. You can operate the drives in various configurations from one enclosure. I used OWC for a while when I used FW800, their stuff was always reliable for me.

With an enclosure like that, you can use the built in hardware RAID or OS X software RAID to set two drives as your primary mirrored set and two drives as your striped backup set.

Although RAID of any kind (other than RAID0 for aggregating storage space) is overkill for home use, IMO, RAID5 is definitely unnecessary unless you simply want the "thrill" of toying with it. Set up a reliable backup system like Time Machine first, then tinker with alternative primary storage options like RAID5 if you are so inclined.