Thank you Stephen, We will do a kernel upgrade as you suggest & then see what is what. We'll do it early tomorrow morning & will let you most helpful people know what happened. Thanks again - great suppport. Regards, Nico Morrison nico.morrison@micronicos.com ___________________________________________ Micronicos Limited - London, UK. Tel: +44 20 8870 8849 Fax: +44 20 8870 5290 ___________________________________________ From: Stephen C. Tweedie [mailto:sct@redhat.com] Sent: 05 February 2003 10:13 To: Nico Morrison Cc: 'Andrew Morton'; ext3 users list Subject: RE: On very different journalling activity on 2 servers. Hi, On Wed, 2003-02-05 at 08:45, Nico Morrison wrote: > [root@ns5 nico]# /sbin/hdparm /dev/hda > /dev/hda: > using_dma = 0 (off) > Does this mean that dma is in fact off? Yes. > Looks like is ON on the server that has no problems and OFF on the one with > loadsa journalling? Yes. > What do we need to do & is it safe to turn DMA ON on a busy working public > internet server? You don't. The trouble is, the kernel usually has a reason for not being in DMA mode. If it can negotiate DMA, it will; but the older of your two systems did not do so, so either that older kernel doesn't know how to drive the IDE controller in DMA mode safely, or it has detected an error on the IDE bus and has backed off to non-DMA mode automatically. In both cases, forcing DMA on manually is not recommended. I'd suggest that you upgrade the 7.2 box to the current errata kernel, which is the same across all the 7.* releases. That should give you the same updated IDE drivers as the 7.3 box has, and will hopefully get you running DMA properly. If it doesn't, then you're going to have to check the logs to see why DMA isn't being negotiated. Cheers, Stephen _______________________________________________ Ext3-users@redhat.com https://listman.redhat.com/mailman/listinfo/ext3-users
