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

[Cristian Livadaru]

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I have found the problem, typical pebkac error!
I had in the fstab these parameters: sync,user,rw,auto,errors=remount-ro
the problem was the sync! that created me the big performance  
problems! :( and I find out about this, AFTER moving all my data and  
transforming the LVM to a raid0
arggg.


On Sep 10, 2006, at 5:14 PM, Cristian Livadaru wrote:

> 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
>>
>>
>>
>> _______________________________________________
>> linux-lvm mailing list
>> linux-lvm at redhat.com
>> https://www.redhat.com/mailman/listinfo/linux-lvm
>> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
>>
>
> --
> Cristian Livadaru
> http://livadaru.net
>
>
>
> _______________________________________________
> linux-lvm mailing list
> linux-lvm at redhat.com
> https://www.redhat.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
>

- --
Cristian Livadaru
http://livadaru.net



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