Solved ZFS mirror with two ssd , worth it?

[wolffnx]

Hi, I have the system installed on one SSD disk, and I put another to act like a mirror. But the mirror is it really worth it on 2 SSD disk?
Because I read here and there about the lifecycle of SSD disk, "one day without warning..dead"

And if I put one normal SATA2 disk to mirror the principal SSD disk, will not suffer the speed of transfers of data?

 

[VladiBG]

Don't mix SSD with HDD. You will be fine with 2 SSD disks in RAID 1.

 

[PMc]

Hi, I'have the system installed on one Ssd disk, and i'put another to act like a mirror
but the mirror its really worth it on 2 Sdd disk?
Because I'read here and there about the cicle life of Ssd disk, "one day without warning..dead"

That's why it should be mirrored.

And if I'put one normal Sata2 disk to mirror the principal Ssd disk, will not suffer the speed of transfers of data?

That tends to behave strange to horrible. ZFS will try to distribute the load intelligently, but will not come to an end with that, because the behaviour of spinning disk is very different (they have seek time, SSD has not).
A mirror of two SSD (different brands) works very nicely here. Don't use the entire SSD. I'm using some part as the SSD-mirrored fast pool, some remainder for L2Arc (unmirrored) for another pool on spinning disks, and a ZIL (mirrored) for another spinning pool, and some remainder left free for the SSD to have internal fun with, and it all works fine together.

Another option would be to use only one SSD, and mirror periodically to a remote machine (or NAS) with zfs send/recv, and that destination can then be on spinning disk. Then when the SSD dies, there will be a few minutes of data loss, and a bit of maintainance work: get a new SSD, plug it into the remote machine and style it up from the mirror. For some laptops with only one bay that might be the only option, and for my desktop it seems good enough to me (I have regular backups also) - it depends on the use-case, the budget and how much work one is willing to accept.

 

[wolffnx]

Another option would be to use only one SSD, and mirror periodically to a remote machine (or NAS) with zfs send/recv, and that destination can then be on spinning disk

Exactly is what I am doing, I don't trust in only one backup system/technique

Don't use the entire SSD

And this one come to your comment:

it depends on the use-case, the budget and how much work one is willing to accept

Budget, the more cheap (and what can I buy) is the Kingston SA400S37/120G
So I am limited in space, works perfect for my desktop, some files here and there.
But for the heavy things (flac music,movies,etc) send to 1TB sata disc.

 

[recluce]

I have a mirrored ZFS on Root on my home server, two 120 GB SSDs. Write speed seems similar to the initial non-mirrored setup (a small decrease, perhaps), read speed is almost twice as fast. And yes, the mirror is there because SSDs are cheap and tend to fail without warning.

 

[rootbert]

What I can recommend: use 2 SSD disks from different manufacturers ... so a firmware bug will less likely lead to data loss. I have not used non-redundant ZFS on any of my systems where more than 1 disk is possible.

 

[wolffnx]

what I can recommend: use 2 SSD disks from different manufacturers ... so a firmware bug will less likely lead to data loss. I have not uses non-redundant zfs on any of my systems where more than 1 disk is possible.

Yes, the mirror one SSD is Western Digital green series (I hate the green series, on SATA and SSD, but.. its what I got)

 

[Argentum]

That's why it should be mirrored.



That tends to behave strange to horrible. ZFS will try to distribute the load intelligently, but will not come to an end with that, because the behaviour of spinning disk is very different (they have seek time, SSD has not).
A mirror of two SSD (different brands) works very nicely here. Don't use the entire SSD. I'm using some part as the SSD-mirrored fast pool, some remainder for L2Arc (unmirrored) for another pool on spinning disks, and a ZIL (mirrored) for another spinning pool, and some remainder left free for the SSD to have internal fun with, and it all works fine together.

Another option would be to use only one SSD, and mirror periodically to a remote machine (or NAS) with zfs send/recv, and that destination can then be on spinning disk. Then when the SSD dies, there will be a few minutes of data loss, and a bit of maintainance work: get a new SSD, plug it into the remote machine and style it up from the mirror. For some laptops with only one bay that might be the only option, and for my desktop it seems good enough to me (I have regular backups also) - it depends on the use-case, the budget and how much work one is willing to accept.

On my desktop I have created a mirror of HDD-s (different brand) and added 2 relatively small (~120GB) SSD-s to the configuration so that I have ZIL mirror on two 16GB partitions of those two SSD-s, L2ARC cache on one the SSD partition 64GB and also /tmp folder on one SSD partition. Everything works smoothly with those hard drives ant nearly SSD speed for most operations but with HDD reliability.