Re: USB 2.0 with 250Gb disk and insane loads

[Terje Malmedal <terje.malmedal@usit.uio.no>]

[Alexander Hoogerhuis]
> Stuck it in an older machine on USB 1.1 and it foudn the disk fine
> (redhat 9, 2.4.20-13.9 kernel on that machine), and ditto result:

> 19:15:16  up 2 days, 20:23,  4 users,  load average: 6.02, 2.41, 0.89
> 58 processes: 55 sleeping, 3 running, 0 zombie, 0 stopped
> CPU states:   0.2% user   4.0% system   0.0% nice   0.0% iowait  95.8% idle
> Mem:   385040k av,  380820k used,    4220k free,       0k shrd,   67368k buff
>        224720k active,              69412k inactive
> Swap:  521632k av,      80k used,  521552k free                  237452k cached
                                                                                
> and generating about 2500 interrupts for the usb controller per 10
> seconds and when i finally break it off and give it "sync" it uses
> about two minutes with about 4500 per 10 seconds to get it all on
> disk. On 2.4 the machine becomes more and more sluggish if I let it
> go more than a short minute.

I had the same problem with USB 1.1. I solved it by writing a
LD_PRELOAD-able shared library which overrides write() to do a
fdatasync() on the filehandle after a megabyte worth of writes.

Would be nice to have it fixed in the kernel though.

-- 
 - Terje
malmedal@usit.uio.no