Lowering the SyncDaemon disk usage

[Marco Trevisan (Treviño)]

I'm sharing with u1 a lot of small files, so when I'm logging in in my account and the syncdaemon starts recheking every file, it really uses too much CPU (as reported by iotop and by UI freezes)...

Of course the sync-daemon has to performs themse oprations, however I guess that this could be done also using a lower ionice class reducing its priority over the GUI (which in my case hangs very much also if using a very recent HW).

Using "ionice -c 3 -p $pid_of_ubuntuone-syncdaemon" which sets the syncdaemon's io-scheduler-class to "idle", really reduce this issue, and I guess that this behavior should be enabled by default in the daemon.

[Andruk (andruk)]

I hope I didn't go outside my purview by marking this bug as confirmed. I can confirm for Ubuntu Lucid, version 1.2.2-0ubuntu2. I will try to check on 10.10 when I install it and report back.

[szemy (sz-tomika)]

Here is part of the man of ionice:
" Note that before kernel 2.6.26 a process that has not asked for
              an io priority formally uses "none" as scheduling class, but the
              io scheduler will treat such processes as if it were in the best
              effort class. The priority within the best effort class will be
              dynamically derived from the cpu nice level of the process:
              io_priority = (cpu_nice + 20) / 5.

              For kernels after 2.6.26 with CFQ io scheduler a process that
              has not asked for an io priority inherits CPU scheduling class.
              The io priority is derived from the cpu nice level of the
              process (same as before kernel 2.6.26)."
If I understand correctly, than setting nice is enough. Now the question: why isn't the sync daemon launched at startup with a high nice(low priority)?

[Pavol Klačanský (pavolzetor-deactivatedaccount)]

Same here, I have a tons of photos synced and it takes about 1 minute or more with high IO to recheck them

[Mikhail Glagolev (mike-glagolev)]

Does anybody know how to change syncdaemon's nice and ionice permanently?