How to cache ZFS pool, Unraid 6.10.1

[Sally-san]

Ok so first time using unraid, im finally getting an understanding of unraid and I'm so close to purchasing my license.

 

My one last issue is trying to cache my ZFS pool.

 

So my config is the following:
Unraid Array : 1 x 32gig flash drive

Cache Pool: 1 x 1tb SSD

ZFS pool: 3 x 16tb HDD is raidz

 

So from what I've seen I can only cache shares that are stored on the array.

I have tried creating a symbolic link from the zpool to a share on the array. The initial zpool directory linked to the share as well as files i put into the folder after linking then get stored on the cache. However once the mover is run and the symlink folder is moved off the cache pool. Any new files copied to the zpool despite having a symlink to the cached share are not cached.

Any help on this would be appreciated.

[Sally-san]

So I figured it out. Instead of using unraids cache pool instead I used zfs l2arc caching which let's you add a cache drive to a pool using this command

 

zpool add *pool* cache *sdX*

[dirkinthedark]

How is this working for you?

[igi]

Hi

I have solved the Problem:

ZFS Pool using unraid Cache Pool

 

system:

HP ML10v2 with 32GB ecc ram and Intel(R) Xeon(R) CPU E3-1271 v3

unraid stick

256 sata ssd

1 TB WD red nvme nas ssd

disk1 is an 16gb usb stick - dummy drive - to start the array

made zfspool with mirror of 2x 16TB

 

I made an zfspool with 2 datasets via Console (you need zfs plugin)

 

like this:
root@media-server:~# zfs list
NAME             USED  AVAIL     REFER  MOUNTPOINT
zfspool         3.73T  10.7T      621M  /zfspool
zfspool/daten    546G  10.7T      546G  /zfspool/daten
zfspool/tausch  3.19T  10.7T     3.19T  /zfspool/tausch

 

 

FIRST start the array

(first time: format disk1  AND format cache via GUI - I'm using xfs)

 

now I mount the zfspool over disk1

so disk1 shows 16TB ! instead 16GB

AND unraid Caching works great !

 

you need this:
mount -R /zfspool /mnt/disk1

 

with -R also the Datasets are mounted !

this datasets are shown as user share in gui - and you can activate cache and smb (public)

tausch and daten

 

you need plugin: user scripts !

so every array start - the pool will mounted

and on array stop it will unmounted

 

mount -R /zfspool /mnt/disk1

   - at startup of array
 

umount -R /mnt/disk1
   - at stopping ofarray

 

so I get 1GB/sec (10gbit ethernet) with cache on - write 10gb video from windows 10 to unraid via SMB

and ca. 250MB/sec without cache - speed of the toshiba 16Tb drives

 

reading same

 

---

ZFS speedup:

creating log and cache files on the 1TB cache drive - I made 2 dummy files for ZFS ZIL/slog and cache/L2arc:

 

dd if=/dev/zero of=/mnt/cache2nvme/CACHE/write bs=1M count=20480        - 20GB file
dd if=/dev/zero of=/mnt/cache2nvme/CACHE/read bs=1M count=409600       - 400GB file

 

now add this drives to your zfspool:

 

zpool add zfspool log /mnt/cache2nvme/CACHE/write
zpool add zfspool cache /mnt/cache2nvme/CACHE/read

 

then it looks like this:

--

zpool status
  pool: zfspool
 state: ONLINE
  scan: scrub canceled on Tue Jan 31 12:33:19 2023
config:

        NAME                                      STATE     READ WRITE CKSUM
        zfspool                                   ONLINE       0     0     0
          mirror-0                                ONLINE       0     0     0
            ata-TOSHIBA_MG08ACA16TE_31P0A1Z5F57H  ONLINE       0     0     0
            ata-TOSHIBA_MG08ACA16TE_31R0A13EF57H  ONLINE       0     0     0
        logs
          /mnt/cache2nvme/CACHE/write             ONLINE       0     0     0
        cache
          /mnt/cache2nvme/CACHE/read              ONLINE       0     0     0

 

-----------------------

 

 

 

 

 

 

Greetings from Hamburg