What ZFS raid configuration for 4 1TB SSDs?

[junior466]

I am about to setup my first TrueNAS box with SSDs for sharing iSCSI for my ESXi hosts but I was wondering what kind of configuration to go with. Performance is my goal and I have strong backups in place but raid0 scares me and I am not considering it. I also do have 10Gb in my rack.

I am leaning towards mirrors or raidz-1 but don't know enough about performance of either in order to choose. And is there anything else I need to know about SSD pools?

My server will have 16GB of DDR4 ECC. I know ZFS loves RAM but this is for two ESXi hosts and about 20 VMs running very light workloads. Would this be enough to start?

 

[NugentS]

Mirrors. That way you get extra IOPS and the drives will wear out in pairs rather than all 4 at the same time
16 GB is very light on RAM - Try 64GB

 

[Scharbag]

Mirrors for IOPS for sure. As said, you should fire more RAM in there for best practices. At least 32GB but 64 would be better.

Are you going to mount iSCSI or NFS in ESXi? If iSCSI, make sure you do round robin on your 10Gig interfaces.

Cheers,

 

[junior466]

Mirrors. That way you get extra IOPS and the drives will wear out in pairs rather than all 4 at the same time
16 GB is very light on RAM - Try 64GB

Good to know! And I will grab more RAM

Mirrors for IOPS for sure. As said, you should fire more RAM in there for best practices. At least 32GB but 64 would be better.

Are you going to mount iSCSI or NFS in ESXi? If iSCSI, make sure you do round robin on your 10Gig interfaces.

Cheers,

I was planning on mounting iSCSI but I want to keep sync off. Is it possible to achieve that as I am not familiar with iSCSI?

 

[NugentS]

Good to know! And I will grab more RAM

I was planning on mounting iSCSI but I want to keep sync off. Is it possible to achieve that as I am not familiar with iSCSI?

You can (I believe) - by setting sync = disabled on the dataset. Warning - you are risking virtual disk corruption that way if you get an unexpected power event

 

[Scharbag]

Good to know! And I will grab more RAM

I was planning on mounting iSCSI but I want to keep sync off. Is it possible to achieve that as I am not familiar with iSCSI?

SYNC is a ZFS feature, not iSCSI - as has been said, be very careful.

And here is memory usage for example:

Services are consuming 23GB on my system. I do have a FT of RAM though, but ZFS is hungry and L1ARC is all RAM based - the more the merrier.

Cheers,