[linux-lvm] Performance problem.

neuron neuron at hollowtube.mine.nu
Mon Nov 17 12:32:02 UTC 2003

>   No,  that  is  true.  Your low read speed does indicate that you are
>   not  using  DMA.  Give  us  the  output of "hdparm /dev/hda". Also a
>   simple  benchmark is to do "dd_rescue /dev/hda /dev/null". What does
>   that give you in numbers?

 multcount    = 16 (on)
 IO_support   =  1 (32-bit)
 unmaskirq    =  0 (off)
 using_dma    =  1 (on)
 keepsettings =  0 (off)
 readonly     =  0 (off)
 readahead    =  8 (on)
 geometry     = 14589/255/63, sectors = 234375000, start = 0

the cables are new (I thought that they may be a problem), I've gotten far better speeds on the same system and a worse system before I used lvm on the same drives.  I REALLY doubt there's something wrong with the drives (I replaced one of them because of an error, and looked for trouble after replacing that one, but didn't find anything else).

And that dd_rescue will read from /dev/hda and write to /dev/null right?  Meaning it's a read test, and not a write test (= I won't loose any data on it ;) ).

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