only one io scheduler available

[DVDIsDead]

as per https://pve.proxmox.com/wiki/IO_Scheduler I tried checking available io schedulers for my drives, they all only specify mq-deadline and none.

```
root@pve:~# cat /sys/block/sda/queue/scheduler
[mq-deadline] none
root@pve:~# cat /sys/block/*/queue/scheduler
none
none
none
none
none
none
none
none
none
none
none
none
none
none
none
none
none
none
none
none
none
none
[mq-deadline] none
[mq-deadline] none
[mq-deadline] none
[mq-deadline] none
[mq-deadline] none
[mq-deadline] none
[mq-deadline] none
[mq-deadline] none
[none] mq-deadline
[mq-deadline] none
[mq-deadline] none
[mq-deadline] none
[mq-deadline] none
```

is this normal?

 

[ITT]

Maybe outdated Wiki...
mq-deadline is the way to go.

Best I/O scheduler to use
Different I/O requirements may benefit from changing from the Ubuntu distro default. A quick start guide to select a suitable I/O scheduler is below. The results are based on running 25 different synthetic I/O patterns generated using fio on ext4, xfs and btrfs with the various I/O schedulers using the 5.3 kernel.

SSD or NVME drives
It is worth noting that there is little difference in throughput between the mq-deadline/none/bfq I/O schedulers when using fast multi-queue SSD configurations or fast NVME devices. In these cases it may be preferable to use the 'none' I/O scheduler to reduce CPU overhead.

HDD
Avoid using the none/noop I/O schedulers for a HDD as sorting requests on block addresses reduce the seek time latencies and neither of these I/O schedulers support this feature. mq-deadline has been shown to be advantageous for the more demanding server related I/O, however, desktop users may like to experiment with bfq as has been shown to load some applications faster.

 

[pringlestuffs]

Personally I would prefer to be able to use bfq on slow spinning drives.

Edit: looks like modprobe bfq works to make the scheduler available.

 

[niziak]

I have one old home PC (ZFS on 2 x HDD + SSD log & cache) turned into PVE. Every backup to PBS cause big delays and slow response even on PVE host. Switching to bfq saves this machine life (Kernel ZFS's processes on lower prio than any other)

 

[丶小樱]

I want to use cfq, it is fairer and has the best performance