[linux-lvm] huge performance problems 25kb/s write speed

Cristian Livadaru cristian at livadaru.net
Sun Sep 10 15:14:10 UTC 2006


I just rebooted with kernel 2.4 instead of 2.6
Now I have a slightly better performance. 3.6mb/s but this still  
isn't optimal.


On Sep 10, 2006, at 4:25 PM, Cristian Livadaru wrote:

> I have since yesterday huge performance problems on my LVM!
> I have 2x 300GB as 1 unstriped LVM.
>
> dd if=/dev/zero of=dd.txt count=500
> 500+0 records in
> 500+0 records out
> 256000 bytes transferred in 9.999764 seconds (25601 bytes/sec)
>
> dd if=/dev/zero of=dd.txt count=500 bs=4096
> 500+0 records in
> 500+0 records out
> 2048000 bytes transferred in 10.020213 seconds (204387 bytes/sec)
>
> After a reboot it worked normal again for a while, now I have the  
> same problem again.
>
> esplendidos:~# pvs
>   PV         VG      Fmt  Attr PSize   PFree
>   /dev/hde1  sharevg lvm2 a-   279.45G      0
>   /dev/hdg1  sharevg lvm2 a-   279.45G   4.00M
>
> esplendidos:~# lvs
>   LV         VG      Attr   LSize   Origin Snap%  Move Copy%
>   sharelv    sharevg -wi-ao 558.90G
>
> esplendidos:~# vgs
>   VG      #PV #LV #SN Attr  VSize   VFree
>   sharevg   2   1   0 wz--n 558.91G   4.00M
>
>
>   --- Volume group ---
>   VG Name               sharevg
>   System ID
>   Format                lvm2
>   Metadata Areas        2
>   Metadata Sequence No  2
>   VG Access             read/write
>   VG Status             resizable
>   MAX LV                0
>   Cur LV                1
>   Open LV               1
>   Max PV                0
>   Cur PV                2
>   Act PV                2
>   VG Size               558.91 GB
>   PE Size               4.00 MB
>   Total PE              143080
>   Alloc PE / Size       143079 / 558.90 GB
>   Free  PE / Size       1 / 4.00 MB
>   VG UUID               LaGWNF-9Ace-li4f-h8z2-SJYk-YeyB-joXznp
>
>
>   --- Logical volume ---
>   LV Name                /dev/sharevg/sharelv
>   VG Name                sharevg
>   LV UUID                zCe6sI-pglI-7yh1-EnL4-gsKo-FOEb-POyVoL
>   LV Write Access        read/write
>   LV Status              available
>   # open                 1
>   LV Size                558.90 GB
>   Current LE             143079
>   Segments               2
>   Allocation             inherit
>   Read ahead sectors     0
>   Block device           253:8
>
>   --- Physical volume ---
>   PV Name               /dev/hde1
>   VG Name               sharevg
>   PV Size               279.45 GB / not usable 0
>   Allocatable           yes (but full)
>   PE Size (KByte)       4096
>   Total PE              71540
>   Free PE               0
>   Allocated PE          71540
>   PV UUID               g3jfAR-Z2Ka-SCgr-08QB-8WBn-5g4h-jXLrn1
>
>   --- Physical volume ---
>   PV Name               /dev/hdg1
>   VG Name               sharevg
>   PV Size               279.45 GB / not usable 0
>   Allocatable           yes
>   PE Size (KByte)       4096
>   Total PE              71540
>   Free PE               1
>   Allocated PE          71539
>   PV UUID               kYQB4j-fYV9-3NUa-g0Sg-H4Bk-Kx5F-wRO9G1
>
>
> hdparm -tT /dev/hde
>
> /dev/hde:
> Timing cached reads:   952 MB in  2.00 seconds = 476.00 MB/sec
> Timing buffered disk reads:  130 MB in  3.00 seconds =  43.33 MB/sec
> esplendidos:/shared# hdparm -tT /dev/hdg
>
> /dev/hdg:
> Timing cached reads:   960 MB in  2.00 seconds = 480.00 MB/sec
> Timing buffered disk reads:  154 MB in  3.01 seconds =  51.16 MB/sec
>
>
> I don't have any errors in logfiles ( syslog/messages/lvm2.log )
> Any hints what else I can check or do to improve performance? I  
> mean 25kb/s on a local HD is more then just slow!
> Please please help.
>
>
> --
> Cristian Livadaru
> http://livadaru.net
>
>
>
> _______________________________________________
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> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
>

--
Cristian Livadaru
http://livadaru.net






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