[olug] Slow read speeds-SuSE

Jay Woods woodsjay at cox.net
Thu Apr 29 13:06:25 UTC 2010


On Thursday 29 April 2010 01:57:58 am Rob Townley wrote:
> On Wed, Apr 28, 2010 at 4:16 PM, Craig Wolf <CJWolf at mpsomaha.org> 
wrote:
> > Ok, my backups from one of my linux servers takes 5 days to
> > finish...my window is 36 hours, not working right.  Throughput of
> > about 1.5GB/hour. So in my testing, copying a 158MB directory to
> > the server takes about 1 Minute 5 seconds.  Copying same structure
> > off the box takes almost 7 minutes.  Network switches show no
> > issues/error.  iostat shows slow to no throughput at all on read.
> > 
> > SO, the million dollar question is, what should I look at for
> > fixing this??  Do I use hdparm?
> > 

I'm getting the same sort of problem copying a file from my hard disk to 
an external disk. Short files (less than 5 GBytes) are at the usual 
speed of 20 MBytes/sec. Big files (about 50 GBytes) slow down to under 1 
MByte/sec during the copy.

> > TIA!!
> > 
> > 
> > Craig Wolf
> > Linux Server Support
> > Data Backups Administrator
> > Desktop/Network Specialist
> > Desk: (402)715-6283
> > Cell: (402)510-0301
> > _______________________________________________
> > OLUG mailing list
> > OLUG at olug.org
> > https://lists.olug.org/mailman/listinfo/olug
> 
> So this backup is probably a bunch of small files.
> Is this machine  or particular filesystem Active Directory joined? 
> In other words, do the files on the partition have a set of
> permissions that need to be accessed from a third system to
> determine if the user is allowed read access?
> If you notice a big difference in time between a 'ls' and a 'ls
> -latr' then it may be a permission problem.
> Long shot, but very simple test.
> 
> So there were two /media/ mounts, so i assume that is read only media
> because there was no space left on those.  But the following (backup
> pool?) is almost full as well.  Is /dev/evms/DATA where the slow data
> is written?
> /dev/evms/DATA            11      11       0  100%
> /opt/novell/nss/mnt/.pools/DATA
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