[DRBD-user] kernel panic on secondary

[Helmut Wollmersdorfer]

Lars Ellenberg schrieb:
> / 2004-07-06 20:58:20 -0300
> \ Marlon Cabrera Oliveira:

>>using_dma    =  0 (off)
[...]
>>/dev/hda:
>>Timing buffer-cache reads:   2048 MB in  2.00 seconds = 1024.00 MB/sec
>>Timing buffered disk reads:   14 MB in  3.09 seconds =   4.53 MB/sec

>>I  setup dma only for disks on kernel.

> and obviously it is not enabled nevertheless.
> maybe your chipset is blacklisted because known

I use some - known as buggy - VIA chipsets in 4 of my boxes and have no 
problems with Kernel 2.4.22 or 2.4.24.

> check wether your chipset is properly supported.

Maybe Marlon should check the base config of DMA first.

# hdparm -d 1 /dev/hda
# hdparm -tT /dev/hda

Now "Timing buffered disk reads" of an Samsung should be around 50 MB/sec.
If not, check chipset, hardware, cables, kernel etc.
If it is, /etc/default/hdparm should be edited to have an entry like

/dev/hda {
	dma = on
}

to make DMA permanent.

Then reboot and do hdparm -tT again.
If the speed again is slow now, hdparm should be updated to the newest 
version. This was my problem, getting DMA permanent for hda, but not 
permanent for hdb, hdc etc. Since upgrade to

helmut at xp2400:~$ hdparm -V
hdparm v5.4

no problems anymore.

Helmut Wollmersdorfer