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Re: kjournald using up majority cpu%.

Administrator wrote:
> Thank you Andrew,
> Is this the same as the checkdma utility that allows turning on & off of DMA
> on Windows?

What's that? ;)

> And as these servers are working linux customer servers - can we change the
> DMA setting & know we can change it back without problems?

You'll need to read the hdparm manpage, and then familiarise yourself
with its usage on a test machine.

The testing should happen during a planned outage - making mistakes
with hdparm can easily take a machine down. 

But the first thing which you should do (which is perfectly safe) is to
just query the settings without attempting to change anything.

mnm:/home/akpm# hdparm -i /dev/hda


 Model=Maxtor 5T040H4, FwRev=TAH71DP0, SerialNo=T4J0N9BC
 Config={ Fixed }
 RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=57
 BuffType=DualPortCache, BuffSize=2048kB, MaxMultSect=16, MultSect=off
 CurCHS=16383/16/63, CurSects=-66060037, LBA=yes, LBAsects=80043264
 IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
 PIO modes: pio0 pio1 pio2 pio3 pio4 
 DMA modes: mdma0 mdma1 mdma2 udma0 udma1 *udma2 udma3 udma4 udma5 
 AdvancedPM=yes: disabled (255)
 Drive Supports : ATA/ATAPI-6 T13 1410D revision 0 : ATA-1 ATA-2 ATA-3 ATA-4 ATA-5 ATA-6 

See that asterisk next to "udma2"?  It means this disk is running
in UltraDMA mode 2, at 33 megabytes/second.  All is well.

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