Does anyone know how to add / make available the deadline I/O schedulers on BusyBox v1.16.1 ? The only two I see when I run "cat/sys/block/sda/queue/scheduler" is as follows:

[noop] cfq

My understanding is that there are two more... anticipatory and deadline, but I don't know how to enable / install them.


  • Um... why? It's not a normal thing to do... – ewwhite Dec 4 '16 at 2:02
  • well.. I have 2 NAS's one that has it.. and one that doesn't, I'm trying to do some performance testing and that's one of the differences I'd like to test.. why do you say it's not a "normal" thing to do? – stumped221 Dec 4 '16 at 2:22
  • busybox is just a shell, not your kernel. The kernel must have included support for the scheduler. – Michael Hampton Dec 4 '16 at 2:51
  • thanks for the response Michael, I'm new-ish to linux so I didn't realize.. here's my kernel: Linux version 3.2.40 (root@nas) (gcc version 4.6.4 20130102 (prerelease) (crosstool-NG 1.18.0) ) #1 SMP Thu Aug 20 15:28:30 UTC 2015 – stumped221 Dec 4 '16 at 2:55

This is a "talk to your vendor" or whoever manufactured the product situation.

More information is always better. If these are NAS devices, why not include the makes/models of the product? If they are the same product, maybe you have different versions of the software loaded.

Are you seeing a performance difference? Is there a problem?

Either way, the answer to your question likely has nothing to do with your I/O scheduler alone, and more to do with the software running the NAS.

  • thanks for the response ewwhite, I suppose there is much more to this story than I let on.. I thought the solution was related to the IO scheduler, but found that they are in fact set the same on both NAS's, so that's obviously not it anyway. I have these two identical NAS's (WD MyCloud). Both were purchased at the same time and are the same model number. On one of the devices I wiped out the WD software fresh (through DD) and installed Debian 6.5 with Samba 4.2.10. After doing that I pulled benchmarks of both and found the WD device to run 104.68 MB/sec and the other 57.08 MB/sec – stumped221 Dec 5 '16 at 2:53
  • At first I thought that the schedulers were set differently as the WD default setup had anticipatory and deadline available, but after checking back, I found it was actually set to CFQ as the Debian box was also. – stumped221 Dec 5 '16 at 2:55

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