Any experts or people with hands on experience who have actually altered the metaslab parameter and know if it works reliably?
I am asking because over the years, as I have upgraded from 4TB drives to now 18TB drives, basically I am losing quite a bit of space to the ZFS ether because of the metaslab issue.
The best articles written on the meta-slab subject are here:
Before there is knee jerk reaction:
I have been using home built multi drive servers using ZFS and FreeNAS/TrueNAS for 8 years now, so I have some experience in what I am doing, so I ask politely not to turn this conversation into a flame war of opinions on how moronic I am for asking this question. (I get it, its not approved or tested.) I am happy to share my experiences and all the mistakes I have made along the way with the community, so I ask for the same generosity as well.
I am not the typical TrueNAS user, meaning I have a large library of video (film archive) with mostly large files that is more less stagnant except for one pool in each server that gets new video added to it. I built it this way for long term reliability, easy expansion, easy to backup to another set of bare drives. Only one user access this storage at a time so through-put is fine they way it is (actually I have 10 Gig net issues I have yet to solve but that's another post.). Yes there us a downside of losing speed efficiency by not making the pools as one big vdev, and I have to manually manage some drive/zfs, but speed is not the issue, reliability and recovery is if we ever lose a vdev.
Here is the Topology as well:
Server 1:
- Storage 1 has Ten 12TB drives in RaidZ2 and is both a Zpool and a vdev (Full)
- Storage 2 has Ten 12TB drives in RaidZ2 and is both a Zpool and a vdev (Full)
- Storage 3 hasTen 12TB drives in RaidZ2 and is both a Zpool and a vdev (Has Free Space)
(30 drives Total)
Server 2:
- Storage 4 has Ten 18TB drives in RaidZ2 and is both a Zpool and a vdev (Full)
- Storage 5 has Ten 18TB drives in RaidZ2 and is both a Zpool and a vdev (Full)
- Storage 6 hasTen 18TB drives in RaidZ2 and is both a Zpool and a vdev (Full)
- Storage 7 hasTen 18TB drives in RaidZ2 and is both a Zpool and a vdev (Has Free Space)
(40 drives Total)
Servers and drives are mostly left off until I need to access. I also do not run a ZIL or SLOG.
Back to my question:
1) Can the meta-slab be altered reliably and with stability?
2) How to make changing the meta-slab variable stick?
I am asking because over the years, as I have upgraded from 4TB drives to now 18TB drives, basically I am losing quite a bit of space to the ZFS ether because of the metaslab issue.
The best articles written on the meta-slab subject are here:
ZFS Capacity Calculator - WintelGuy.com
ZFS / RAIDZ Capacity Calculator - evaluets performance of different RAIDZ types and configurations
wintelguy.com
Before there is knee jerk reaction:
I have been using home built multi drive servers using ZFS and FreeNAS/TrueNAS for 8 years now, so I have some experience in what I am doing, so I ask politely not to turn this conversation into a flame war of opinions on how moronic I am for asking this question. (I get it, its not approved or tested.) I am happy to share my experiences and all the mistakes I have made along the way with the community, so I ask for the same generosity as well.
Here is the Topology as well:
Server 1:
- Storage 1 has Ten 12TB drives in RaidZ2 and is both a Zpool and a vdev (Full)
- Storage 2 has Ten 12TB drives in RaidZ2 and is both a Zpool and a vdev (Full)
- Storage 3 hasTen 12TB drives in RaidZ2 and is both a Zpool and a vdev (Has Free Space)
(30 drives Total)
Server 2:
- Storage 4 has Ten 18TB drives in RaidZ2 and is both a Zpool and a vdev (Full)
- Storage 5 has Ten 18TB drives in RaidZ2 and is both a Zpool and a vdev (Full)
- Storage 6 hasTen 18TB drives in RaidZ2 and is both a Zpool and a vdev (Full)
- Storage 7 hasTen 18TB drives in RaidZ2 and is both a Zpool and a vdev (Has Free Space)
(40 drives Total)
Servers and drives are mostly left off until I need to access. I also do not run a ZIL or SLOG.
Back to my question:
1) Can the meta-slab be altered reliably and with stability?
2) How to make changing the meta-slab variable stick?
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