Re: System unresponsitive when copying HD/HD

[Alan Cox]

> If I have vmstat running, I notice blocks trickling out to the disk, 5sec averages
> 495,142,151,155,136,257,15,0.  Note that the maximum read rate (hdparm -t) of this
> disk is in the 12-14M/s range.  I'm getting about 1-5% of that on output with the
> system's disk subsystem being apparently unable to do anything else.
> 
> This is with IDE hard disk with DMA enabled.
> 
> a) is this expected performance on a large linear write?  

No

> b) should I expect other disk operations to be denied service as long as
> 	the write is 'flushing'?

No

But try 2.4.1 before worrying too much. That fixed a lot of the block 
performance problems I was seeing (2.4.1 ruins the VM performance under paging
loads but the I/O speed is fixed ;))