On Tue, Nov 25, 2008 at 04:56:24AM -0500, Justin Piszcz wrote:barriers enabled:
$ time bash -c 'tar xf linux-2.6.27.7.tar; sync'
block 573932: ** Block of NULs **
Total bytes read: 293857280 (281MiB, 1.9MiB/s)
real 2m40.643s
user 0m0.194s
sys 0m1.541s
barriers disabled:
time bash -c 'tar xf linux-2.6.27.7.tar; sync'
block 573932: ** Block of NULs **
Total bytes read: 293857280 (281MiB, 11MiB/s)
real 0m27.612s
user 0m0.182s
sys 0m1.617s
That's worse than usual, and even the no-barriers numbers are still
really bad. What kind of disk and controller is this? Did you
try to disable the cache with hdparm and see what that gives?