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FreeNAS: Open Source Storage Operating System

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Re: FreeNAS: Open Source Storage Operating System

#131

Post by feld »

feld wrote: post #119
NeutronBoy wrote: post #108

Earlier quoted context omitted.

I used ZFS in two production instances a few years ago on Solaris, and had two instances of a bug that totally corrupted the superblock on each drive, meaning that all data was gone with no way to recover. Now I'm back to HW RAID, LVM, and ext4, which works a treat, and I'll be using that until I have more faith in ZFS.

You had incredibly bad luck then unless you weren't running Solaris on Sun hardware, in which case you may have shot yourself in the foot with a poor disk controller and/or no ECC.

is it not obvious that you can't pull any hardware out of the bin and expect ZFS to be OK with it? it has requirements just like many modern OS features. Run virtualization without any CPU extensions to accelerate it and then tell me you're upset when your VMs kill your host with excessive resource consumption.

Re: FreeNAS: Open Source Storage Operating System

#132

Post by cyphar »

jmporcel wrote: post #101
eric_the_read wrote: post #92

Earlier quoted context omitted.

Can you do btrfs with FreeNAS? I didn't think that was available.

If you could, that makes no sense. ZFS is superior.

Unless you want to reshape your array. Then md-raid is superior. Btrfs's raid implementation has had some pretty bad issues recently and has been declared "experimental" as a result.

Re: FreeNAS: Open Source Storage Operating System

#133

Post by ultramancool »

cyphar wrote: post #126
ultramancool wrote: post #11

Earlier quoted context omitted.

Those 3TB Seagate drives are literally the worst in the business. The 2TB and 4TB are pretty good (roughly on par or better than competitors according to the backblaze reports) but those 3TB drives were utter shit for some reason, ~20% year over year failure rates. Some retailers have even started to sell the 3TB Seagate drives at almost the same price as the 2TB ones. Probably the only way to get rid of them.

Please remember that back blaze was cracking open external hard drives in that case. Also, at the time, one of the large HDD manufacturers lost their main build plants. So who knows where Seagate got their components from in that 1-2 year period. Given the fact that Seagate's 4TB hard drives are considered by back blaze as the best HDDs, I find it a little odd that everyone assumes that manufacturing issues 4 years a…

I've anecdotally experienced very high failure rates on them too, had 3/6 fail in about 5 years. And many other anecdotal reports indicate similarly bad results. Maybe not as bad as Backblaze but pretty damn bad.

I absolutely agree though, the 4TB are a great improvement, you can't beat them for reliability unless you're really willing to pay for it. I've chosen them for my personal NAS and some servers even with great results so far.

Re: FreeNAS: Open Source Storage Operating System

#134

Post by js2 »

zippergz wrote: post #129
TheAceOfHearts wrote: post #128

This is probably a really stupid question, but for what kinds of applications or scenarios are people using FreeNAS? I'm interested in hearing about regular users, not business or enterprises. Upon seeing FreeNAS Mini, I have to say that I'm really interested. I've become increasingly uncomfortable with the idea of keeping all of my data "in the cloud". Being able to keep a local version of all my media would help gi…

I use FreeBSD+ZFS rather than FreeNAS, but it's the same idea. I store all of my photos and videos, all of my music, and all of my movies. The music and movies are served via Plex and Sonos to various parts of the house, and I use Lightroom to browse the photos. This is not the only copy of any of this stuff, though. The photos get synced to S3 and backed up on a second local hard drive. All of the movies I have are…

How are you accessing the photos? NFS? SMB? Is the performance decent?

Re: FreeNAS: Open Source Storage Operating System

#136

Post by pixl97 »

jzelinskie wrote: post #21
tracker1 wrote: post #8

Although I don't think I'd ever DIY another NAS box, I would suggest the following, use a common chipset controller that exposes each drive/device separately with all information, some don't. Also, prefer a system with ECC, Asus supports ECC on most AMD FX supporting motherboards for the less expensive option there. Also, have 2 spare drives on hand. I went back to Synology after my uper-nas crashed and burned (reall…

I wanted to do something like this, but after reading about the failure rates of drives and raid, once one disk fails, it seems like you're fucked. Anybody got some stories or numbers that prove that while repairing my raid for one disk failure I won't just destroy the rest of my drives?

Most raid failures are the fault of the user not understanding how raid works and leaving their raid improperly managed.

First, buy good drives. Buying desktop drives that suck are a great way to end up with a corrupt SAN. In general you want drives that support TLER so if something goes wrong, you hear about it right away, rather than the drive trying to fix the problem silently while causing the disk to have long delays. You don't have to go super expensive enterprise, but buying from the bottom of the barrel, or is a 'green' or efficient drive is a great way to lose data.

Second, no matter if you are using hardware or software raid, set up the monitoring utilities properly. You need an immediate alert if a drive is going bad or has failed. SMART should be enabled and when it alerts, replace the drive. The software should also do a verify, patrol read, or scrub (different terms for the same thing) that occasionally check the surface media of the disk and the validity of the data. If anything comes back with an error, you replace the disk right then.

Lastly, one of the big issues why people lose raids all at once is they go out and buy a huge stack of the same kind of disk, made on the same day, with the same firmware, and possibly the same inattentive QA person. Sometimes when problems crop up, it can be a systemic problem with that model, and when all you have is one model, bye bye everything.

Re: FreeNAS: Open Source Storage Operating System

#137

Post by pixl97 »

ultramancool wrote: post #46
jzelinskie wrote: post #21

Earlier quoted context omitted.

I wanted to do something like this, but after reading about the failure rates of drives and raid, once one disk fails, it seems like you're fucked. Anybody got some stories or numbers that prove that while repairing my raid for one disk failure I won't just destroy the rest of my drives?

> I wanted to do something like this, but after reading about the failure rates of drives and raid, once one disk fails, it seems like you're fucked. Anybody got some stories or numbers that prove that while repairing my raid for one disk failure I won't just destroy the rest of my drives? Yeah, I've recovered several failed drives without issue, even on LVM systems where some partitions failed because they were stri…

RAID6 is pretty safe. If you're using ZFS that's a RAIDZ2, you can lose 2 drives in a volume.

RAID5 can be pretty risky with large drives that are the same type.

>conflicting data between 2 drives, but I've never seen that happen in the real world

Heh, run enough servers and you'll see everything eventually. Had a really fun one where a hardware raid card was telling us that writes were successful, but when data was coming back corrupt. It was writing bad data to two of the drives in the array.

Re: FreeNAS: Open Source Storage Operating System

#138

Post by pixl97 »

NeutronBoy wrote: post #108
BrainInAJar wrote: post #47

Earlier quoted context omitted.

it's ZFS backed, screwing up the RAID is going to be pretty close to impossible. you can lose the system disk (usb key) that holds your settings, but the data you actually care about will be safe.

I used ZFS in two production instances a few years ago on Solaris, and had two instances of a bug that totally corrupted the superblock on each drive, meaning that all data was gone with no way to recover. Now I'm back to HW RAID, LVM, and ext4, which works a treat, and I'll be using that until I have more faith in ZFS.

Wait till you have a HW raid silently write bad data.

Nothing is safe.

Re: FreeNAS: Open Source Storage Operating System

#139

Post by codemac »

bcantrill wrote: post #106
codemac wrote: post #35

Earlier quoted context omitted.

> Two copies would not help to determine which bit is the correct one, you would need three. Once you have these, I guess you would be able to detect corruption. Am I guessing correct that duplication beyond 3 times would just help with read speed and in the case when a drive fails while one is already dead (e.g. when you are rebuilding)? You're confusing two topics. Integrity vs. availability. 3x copies, RAID4 XOR,…

It seems that you might have edited your penultimate sentence, but just to make sure that the record is unequivocally clear on this: NetApp and Sun didn't simply "sue each other", NetApp initiated patent litigation against Sun in East Texas, and Sun countersued as a defensive maneuver.[1] As for your ZFS question, Bonwick's blog is certainly a good source -- though if one is looking for a thorough treatment, I might…

I did not edit that part IIRC, I try not to edit anything substantially that I post online.

As far as NetApp v. Sun, it was very unfortunate. I could rant for days about how crappy the business reasons were for NetApp going after Sun (zomg coraid!).

I use your quote about Oracle being a lawn mower from your usenix presentation all the time. Thank you for your reply.

Re: FreeNAS: Open Source Storage Operating System

#140

Post by pixl97 »

voltagex_ wrote: post #113
acd wrote: post #98

ZFS runs with even better performance when you turn compression on. zfs set compression=lz4

I noticed a massive write performance hit when I enabled this. Note that it'll only compress data after you enable it, it isn't retroactive

What CPUs do you have in your box?

In most modern systems the rate at which the CPU can compress data is many, many times faster than the disk can write data. In general compression greatly increases write speeds because less disk IO is needed. The vast majority of benchmarks show that to be the case too.

TL:DR, if you notice a performance decrease after enabling compression, something is wrong with your NAS/SAN.

That said, if you are just storing large encrypted files on your ZFS then compression isn't needed.

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