[7.2-7] IO problems

Hm. just for completeness. I am thinking about how to run the whole thing as soon as the new SSDs arrive.
What would you suggest? Do you think it is sufficient to let system and non-critical VMs (like mail-server with > 300GB) on the consumer disks and move only "critical" vms (like home automation, asterisk, firewall and so on) to the enterprise disks?
 
The consumer SSD is not per se a slow storage, it is only slow when a lot of writes happen, so having VMs that don't write much will be fine. This can be a file storage (e.g. media) and probably a mailserver if there is not written much.

PVE itself should also be on the enterprise SSDs, PVE writes also a log (PVE filesystem in /etc/pve and RRD graphs).
 
imho, your consumer ssd slowdown because hw raid doesn't support / expose trim, check wear level on motherboard ahci sata port.
consumer ssd is ok on ext4/lvm outside hw raid or hw raid in it mode because trim support.
i've one system with 1 consumer ssd then daily backup on second ssd, not really raid but acceptable alternative for this system.
many people here use zfs software raid with their entreprise-class ssd, isn't it ?
 
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imho, your consumer ssd slowdown because hw raid doesn't support / expose trim, check wear level on motherboard ahci sata port.
consumer ssd is ok on ext4/lvm outside hw raid or hw raid in it mode because trim support.
i've one system with 1 consumer ssd then daily backup on second ssd, not really raid but acceptable alternative for this system.
many people here use zfs software raid with their entreprise-class ssd, isn't it ?
thanks, but I am using a LSI MegaRAID SAS 9240-4i controller for this SSDs, not the motherboard ones...
 
thanks, but I am using a LSI MegaRAID SAS 9240-4i controller for this SSDs, not the motherboard ones...
so you can't check wear level of your ssd because of raid controller, unplug all disks, plug one ssd temporarily to motherboard then just check wear level using live cd , don't boot pve, you'll have the explanation of the slowdown of yours ssd.
 
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does not sound so good. but I had those lags from the beginning. did never hear of wear-level before.
and yes, I am using hw-raid
 
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but I had those lags from the beginning. did never hear of wear-level before.
Yes, it's (not only) trim, it's the consumer grade quality with less performant chips and caching in place.

do you use RAID ? hw raid ? zfs ? if yes how many RAM ?
We use all variaties dependend of their use case (all SSD-only or stated otherwise):
- systems with an external SAN (e.g. cluster nodes), only hardware raid (all enterprise) of 2 or 3 SSDs in RAID1
- system with local storage (ZFS) and also in conjunction with harddisks as special devices in a ZFS hybrid pool
- local systems with hardware RAID if ZFS was not possible (e.g. for Oracle databases, ZFS is not supported on non-solaris machines)

My local (home) system is the smallest with only 16 GB-RAM with RAID1 on 2 Samsung SSDs and only LX(C) containers.
 
@LnxBil: just to let you know what happened.
I ordered two enterprise level ssds (500GB, used) and installed them on the very same controller as the consumer-level ssds, also as raid-1.
I did not want to re-setup everything so I kept / of the host on the consumer disks, but when moving a 30GB vm disk from classical disks to consumer ssds using pve, it takes about 30 mins (!). doing the same to enterprise-level ssds it takes under 3 mins (!!!).
I never would have beleived that.just moving my time-critical vms (like opnsense, fhem home automation and so on) to the enterprise-level disks and letting machines like mail server (> 300GB) on the consumer disks.
Thanks for this hint man!
 

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