RAID1 or RAIDZ2

[bmcclure937]

Thanks for the input. I am not planning to use ZFS mirror in lieu of a backup strategy.

That being said, I understand your suggestion to have 2 ZFS mirror (one prod, one backup) to withstand 3 drive failures.

I do not have the money to spend on 4x HDD at this time to only get 25% usable space. I will stick with 2x5TB drive in ZFS mirror and add a backup drive once I start to accumulate enough data to be concerned with backup.

 

[Mirfster]

Just adding a point that often times the decision to "make it right later"; usually don't happen. Not saying this is your case, just in general. Usually once things "appear" to be running fine, the original desire to have appropriate backups kind of goes out the window. Of course, this happens all too often and it is then that once the data is lost that hindsight kicks in.

For some, the rule of thumb is that if you don't have the data in at least three different places; then you don't have the data...

FreeNas is awesome; but nothing is 100% bulletproof.

 

[bmcclure937]

Just adding a point that often times the decision to "make it right later"; usually don't happen. Not saying this is your case, just in general. Usually once things "appear" to be running fine, the original desire to have appropriate backups kind of goes out the window. Of course, this happens all too often and it is then that once the data is lost that hindsight kicks in.

For some, the rule of thumb is that if you don't have the data in at least three different places; then you don't have the data...

FreeNas is awesome; but nothing is 100% bulletproof.

Thanks for the reply. Appreciate it.

I fully understand where you are coming from and your comment applies to a lot of projects. If you do not do it right the first time around but do enough to get things working... then it is easy to forget to come back and add the finishing touches.

My background is in IT and I manage a number of projects where I see this happen. It can be difficult to convince the business partners to spend a little extra up front for a proper implementation long-term.

That being said, this is my home media server and the data is not life critical. We will also use to backup files (which will be stored elsewhere). We will not be using this as a primary file server or anything critical. I would still like to leverage ZFS mirror and backup but will probably not go all out with ZFS RAIDZ2, RSYNC backup, and off-site storage of backups. :)

 

[Mirfster]

Not a problem, sounds to me like you are well versed. Just was "preaching the gospel". :D

Edit: Corrected to be "are well versed"...

 

[Ames]

This has been a very informative read and exactly the type of information I was looking for. I've read arguments for mirroring (raid1, an industry standard to describe mirroring) instead of using raidz1 or raidz2, due to the complexity of parity checks, I/O performance, and time to repair here.

My aging raidz1 pool on is starting to die with Seagate Red 4Tb drives. Copying information out from the pool no longer reads from the ailing disk, which I interpret to mean the disk or the entire pool is about to die. I have another 4 disk raidz2 in another box, but it doesn't have as much capacity as the raidz1 pool, perhaps due to segmented poo. Both systems have 4 Tb Seagate Reds at 5900rpm built about a year apart.

I'm contemplating the best course of action going forward.
Option 1: Replace the 4x 4Tb disks with HGST 8Tb disks @$299 ea. to replace the raidz2 pool [$1196], then use the removed 4Tb disks as spares to repair the raidz1 pool.
Option 2: Buy 2x Seagate 10TB Ironwolf ($379) and mirror them as storage pool [$758]. I've notice my raidz2 pool sucks at disk I/O as compared to the raidz1 pool, both at 5900rpm.

At $438 difference. I suspect the mirrored Ironwolf at 7200rpm would fly in disk I/O as compared to HGST also at 7200rpm configured in a 4 disk raidz2. It's the safety vs speed vs cost considerations.

Interested in what others have implemented whether it be mirroring vs raidz2. Please be mindful of your response, as I'm not looking for a flaming war on implementation, but for experience from the freenas/zfs community.

 

[Mr_N]

My aging raidz1 pool on is starting to die with Seagate Red 4Tb drives. Copying information out from the pool no longer reads from the ailing disk, which I interpret to mean the disk or the entire pool is about to die. I have another 4 disk raidz2 in another box, but it doesn't have as much capacity as the raidz1 pool, perhaps due to segmented poo. Both systems have 4 Tb Seagate Reds at 5900rpm built about a year apart.

Well this is obviously because one is a z1 pool and one is a z2 pool ...

I would replace the z1 pool all together (may only be 1 bad drive and you could reuse the rest to increase the size of your z2 pool after you move the data off it), with what really depends on what your using it for... the 2 obvious options are a 2nd z2 pool or a pool of mirrors with the drive sizes dependent on your storage needs now and into the future.