Is it posible for multiple zpools to use the same cache disk ?

[vn_mnm]

And if possible, PLP.

If obtaining an Intel Optane is too costly or stock being unavailable for me, can I look at Innodisk SATA SSDs with PLP ?

Stability ❘ iCell Technology – Innodisk

Innodisk iCell Technology ensures that DRAM-based solid-state drives (SSDs) can protect mission-critical data and prevent data loss during an unexpected power failure.

www.innodisk.com

 

[vn_mnm]

Setting on sync writes IS a performance killer.

About my CCTV pool, how can data written to it from the CCTV vm (docker) being asynchronous?

 

[Patrick M. Hausen]

If obtaining an Intel Optane is too costly or stock being unavailable for me, can I look at Innodisk SATA SSDs with PLP ?

I don't know. Ask the vendor about the sustained write rate and the TBW number. Pick a device from the "approved devices" thread in this forum or do whatever you want to do but don't come back when you lost data.

And again: sticking an SLOG into a pool with asynchronous writes WILL NOT SPEED UP ANYTHING.

About my CCTV pool, how can data written to it from the CCTV vm (docker) being asynchronous?

The system inside the VM issues a write system call which is executed by the bhyve hypervisor inside TrueNAS which is delegated to ZFS which handles it asynchronously by writing to RAM and immediately acknowledging. Unless you set sync=always in which case it will be synchronous. And orders of magnitude slower. And still slower with an SLOG but faster than without.

 

[vn_mnm]

Unless you set sync=always in which case it will be synchronous.

I see. Just curious, If written data to the CCTV zpool is asynchronous , how can I watch or record from the cameras in real time ?

 

[Patrick M. Hausen]

Inside the VM there will be sync or async writes however your application and the VM's guest OS decide. I am only talking about how ZFS commits these writes to a virtual disk to your real disks/SSDs in the end.

 

[sretalla]

how can I watch or record from the cameras in real time ?

I think you're not grasping the time scale (and mechanism)... We're talking very small amounts of time and on top of that, all data not yet confirmed is in RAM and can still be accessed if it's requested before the write is completed to disk.

 

[vn_mnm]

Only the manufacturer could tell, but partitioning is likely to have adverse effects.


Just a (good) consumer drive.
No PLP: Not suitable for a SLOG (which you probably do not need) under any circumstance.
And not the data centre-grade endurance one would like for a L2ARC (assuming you have enough RAM already).

Use the P31 as system drive in a desktop, or to host VM/containers in SCALE.

If you do have a use for a SLOG, get an Optane or Radian RMS.
If you do have a use for a L2ARC, get a data centre SSD with a decent DWPD rating.

If I am to use my 2x SK Hynix P31 to host the VMs, which ZFS configuration for it should I use, buddy ?

 

[Patrick M. Hausen]

Build a separate pool from these two SSDs - mirrored vdev - put VMs on that pool, done. What do you mean by "ZFS configuration"?

 

[vn_mnm]

What do you mean by "ZFS configuration"?

I mean the RAID-Z configuration. But you have just answered me with 'mirroring', so thank you very much buddy.