FreeNAS as a backup device?

[danb35]

RAID1 on > 1TB drives is IMHO just not useful; rebuild just takes too long, if it works.

By all accounts, this is fundamentally incorrect.

I have some experience with UPSs, IMHO they are very expensive, need constant monitoring and often let me down.

Interesting; this is quite the opposite of my experience.

Edit: ZFS is more tolerant than most other filesystems of power loss, but it isn't a good thing for any filesystem.

 

[Chris Moore]

FreeNAS has a service that allows you to monitor the UPS and automatically shutdown the system when the battery is low.

Sent from my SAMSUNG-SGH-I537 using Tapatalk

 

[wblock]

RAID1 on > 1TB drives is IMHO just not useful; rebuild just takes too long, if it works.

Remember that ZFS does this differently from typical "hardware" RAID. Only used blocks are resilvered, because ZFS knows which blocks those are.

Is it being suggested that the lack of a reliable power supply is a way to loose my zpools?

No, just that a reasonable level of protection makes sense. Having ECC to protect against memory errors, redundancy to protect from disk failure, but nothing to protect from power fluctuation leaves a potential weak spot in the system. And one that realistically does cause problems, usually at the worst possible moment.

 

[Chris Moore]

I am happy to go with raidz2 with carefully purchased disks.

That is one of the other nice things about ZFS, you don't need to be that careful about purchasing your disks. I have been running a series of FreeNAS servers since 2011 and I have gone through a lot of reconfigurations that were all about me wanting something different, I have not lost any data that was committed to ZFS. I think it is the best. I built my first NAS using all second hand part, including the hard drives. I bought a bunch of drives from eBay and when I got them in and built my NAS, I found that some of them were already over 50000 hours of service when I got them. Due to my use of used drives, I had a massive number of drive failures during my first few years. There were months when I replaced a drive every week and I had two drives start going out on the same day one time. I have had a SAS controller fail taking half the drives in my NAS offline while the rest were still working. I have had more hardware failures than I can tell you about without spending more time on the telling than I want to spend on it. I didn't keep a count, but I have easily done 30 or more drive replacements and even replaced two drives at once in a RAID-z2 pool... The point being, even with all those failures, I never lost any data. Even in the system where a controller failed, once I replaced the controller, it came right back up with no lost data.

I get less than 10 power cuts a year, but at least one of those will be long enough to cause my APC smart ups 1500 to totally collapse.

You are supposed to shutdown the system when the power goes out, not count on the UPS to bridge the gap. The battery runtime is to allow a graceful shutdown. Thankfully, FreeNAS has a UPS monitoring service built-in, so when the battery power gets low, it can initiate a shutdown for you even if you are not home or your sleeping in the other end of the house. The UPS monitoring service can also report on the health of the batteries, which must be replaced periodically just like a car battery. I have UPS devices running in my home that are on their third set of batteries and are still doing their job, and they are all APC.

In which case would an alternate strategy be to keep the system spun down except when a backup or restore was in progress.

No, because one of the strengths of FreeNAS is the testing and maintenance it does on the storage pool (you must set the schedule) but it does that work when you are not using the pool. There are drive SMART tests to detect faults early so a failing drive can be replaced before it takes the pool out and there are the scrubs of the data to detect and repair any data errors using the checksum and parity data of the pool. This guards against bit-rot and the system needs to be on for these things to happen.
The best thing you can do for your data is to store it in a ZFS pool. It is better than any other way to store your data. I would go so far as to say it should be the primary storage and have a second FreeNAS server as a backup storage and dispose of any other storage devices you had in the past.

 

[wblock]

You are supposed to shutdown the system when the power goes out, not count on the UPS to bridge the gap.

It depends on the length of the outage. In many places, quick flickers of an outage or raised or lowered voltages are common, and a good UPS helps with all of those.

 

[Chris Moore]

It depends on the length of the outage. In many places, quick flickers of an outage or raised or lowered voltages are common, and a good UPS helps with all of those.

I know, that is why I said 'power goes out' instead of 'when the power flickers' and in the next couple sentences I talked about the USP service in FreeNAS that will shut the system down gracefully when the UPS battery gets low.