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I want to use two schedulers since I have a two Disks set for my system due to a separate HOME disk. Meaning I have SDA and SDB

Doing echo noop /sys/block/sda/queue/scheduler says permission denied with SUDO

I tried the suggested solution but it doesn't work anymore

/etc/udev/rules.d/60-schedulers.rules
ACTION=="add|change", KERNEL=="sda", ATTR{queue/scheduler}="noop"
ACTION=="add|change", KERNEL=="nvme0n1", ATTR{queue/scheduler}="noop"
cat /sys/block/nvme0n1/queue/scheduler 
[none] mq-deadline

The setting is to be system-wide

It could be like this

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash elevator:sda=noop elevator:nvme0n1=noop"

Is this the correct line or do I need a comma between the two disk parameters?

5
  • While not ideal, you could schedule that command in rc.local or with systemd to run on startup. The link below refers to upstart, which I believe is outdated but related. askubuntu.com/a/910/647604 – brndn2k Mar 10 '17 at 23:49
  • There's a Debian Wiki entry that describes one method: sudo -i followed by apt install sysfsutils followed by echo "block/sda/queue/scheduler = noop" >> /etc/sysfs.conf. That line might be wrong and need to be removed and then replaced using none instead of noop. – Chai T. Rex Mar 11 '17 at 0:30
  • @ChaiT.Rex How do I get this command's man page ? – userDepth Mar 11 '17 at 1:27
  • There's no real command or man page for the file. The contents of /etc/sysfs.conf after you install the package have a bit of an explanation of it, though. – Chai T. Rex Mar 11 '17 at 3:01
  • @userDepth - Deleted the answer as requested. – AnotherKiwiGuy Mar 11 '17 at 8:11
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You should use udev rule for that.

/etc/udev/rules.d/60-schedulers.rules

ACTION=="add|change", KERNEL=="sda", ATTR{queue/scheduler}="deadline"
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  • I think Noop is no longer available in Ubuntu – userDepth Nov 18 '20 at 11:53
  • 1
    Now it's "none" instead of noop for SSD's – userDepth Nov 18 '20 at 12:07

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