[K12OSN] hdparm reveals RAID controller error. Should I recompile kernel?

[John Baillie]

On Fri, 2004-11-05 at 11:42, Dean Weiten wrote:

snip ---------------------------------------->

What kind of hard drives? IDE's are slower, but it really only shows up
in heavy multiuser use. 'hdparm -t -T /dev/hda' should show 40+MB/sec
for the buffered disk reads. If it is a lot less you might have a cable
problem.

> I had assumed that second copies would load faster - but that is not
the
> case.

How much RAM do you have?

---
  Les Mikesell
   les at futuresource.com



This thread caught my attention so I ran hdparm on both of our K12
servers just to see what the results would be. 

On the Dell Poweredge I got the following.

-------------------------------------------------------------
   [root at isadore tmp]# hdparm -t -T /dev/sda2
 
   /dev/sda2:
    Timing buffer-cache reads:   820 MB in  2.00 seconds = 410.06 MB/sec
   BLKFLSBUF failed: Inappropriate ioctl for device
   Timing buffered disk reads:  132 MB in  3.05 seconds =  43.21 MB/sec
   BLKFLSBUF failed: Inappropriate ioctl for device
--------------------------------------------------------------



A little googling lead me to the following regarding the RAID
controller.



------------------------------------------------------------------
   aacraid is included in kernels 2.6.x already. Mark Havercamp is the
maintainer, with assistance from Mark Salyzyn.
   enable CONFIG_EXPERIMENTAL=y and CONFIG_SCSI_AACRAID={y,m} 
------------------------------------------------------------------



Would it be best to recompile the kernel with this or pass this to the
kernel at run time?

According to the following I will have to recompile either way.




------------------------------------------------------------------

   /proc/config is only available in your kernel if you apply a patch
and enable it using CONFIG_PROC_CONFIG when you compile.

   /proc/config is actually pretty handy -- it shows you the
compile-time configuration settings for the kernel:

       $ head /proc/config
        CONFIG_X86=y
        CONFIG_UID16=y
        CONFIG_EXPERIMENTAL=y
-----------------------------------------------------------------


John