From: Errol Neal <eneal@businessgrade.com>
To: linux-lvm@redhat.com
Subject: [linux-lvm] Why is my LVM Mirror performance so bad?
Date: Sat, 27 Sep 2014 13:42:34 -0400 [thread overview]
Message-ID: <1411839754687039500@businessgrade.com> (raw)
Hi There. Hoping to get some clarity on some performance woes in a little testing environment that I've setup.
I am experimenting with LVM mirrors on a CentOS 6.5 cluster.
I have two VMs running on ESX5.5 that are sharing two RDM luns from an SRP target server running SCST.
Performance however seems to take a huge hit compared to a vanilla volume
[root@scst1 ~]# vgs
VG #PV #LV #SN Attr VSize VFree
hadata 2 5 0 wz--nc 999.99g 149.99g
vg_scst1 1 2 0 wz--n- 39.51g 0
[root@scst1 ~]# lvs -a -o +devices
LV VG Attr LSize Pool Origin Data% Move Log Cpy%Sync Convert Devices
mirror1 hadata mwi-a-m--- 100.00g 100.00 mirror1_mimage_0(0),mirror1_mimage_1(0)
[mirror1_mimage_0] hadata iwi-aom--- 100.00g /dev/sdb1(0)
[mirror1_mimage_1] hadata iwi-aom--- 100.00g /dev/sdc1(0)
mirror2 hadata mwi-a-m--- 100.00g 100.00 mirror2_mimage_0(0),mirror2_mimage_1(0)
[mirror2_mimage_0] hadata iwi-aom--- 100.00g /dev/sdb1(25600)
[mirror2_mimage_1] hadata iwi-aom--- 100.00g /dev/sdc1(25600)
mirror3 hadata mwi-a-m--- 100.00g 100.00 mirror3_mimage_0(0),mirror3_mimage_1(0)
[mirror3_mimage_0] hadata iwi-aom--- 100.00g /dev/sdb1(51200)
[mirror3_mimage_1] hadata iwi-aom--- 100.00g /dev/sdc1(51200)
mirror4 hadata mwi-a-m--- 100.00g 100.00 mirror4_mimage_0(0),mirror4_mimage_1(0)
[mirror4_mimage_0] hadata iwi-aom--- 100.00g /dev/sdb1(76800)
[mirror4_mimage_1] hadata iwi-aom--- 100.00g /dev/sdc1(76800)
test hadata -wi-a----- 50.00g /dev/sdb1(102400)
lv_root vg_scst1 -wi-ao---- 31.65g /dev/sda2(0)
lv_swap vg_scst1 -wi-ao---- 7.86g /dev/sda2(8102)
[root@scst1 ~]# dd if=/dev/sdb1 of=/dev/null bs=1M count=20000
20000+0 records in
20000+0 records out
20971520000 bytes (21 GB) copied, 41.0031 s, 511 MB/s
[root@scst1 ~]# dd if=/dev/hadata/test of=/dev/null bs=1M count=20000
20000+0 records in
20000+0 records out
20971520000 bytes (21 GB) copied, 44.344 s, 473 MB/s
[root@scst1 ~]# dd if=/dev/hadata/mirror1 of=/dev/null bs=1M count=20000
20000+0 records in
20000+0 records out
20971520000 bytes (21 GB) copied, 365.685 s, 57.3 MB/s
Is this just the life of a LVM mirror and the performance here is about as good as it gets?
next reply other threads:[~2014-09-27 17:42 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-27 17:42 Errol Neal [this message]
2014-09-27 20:35 ` [linux-lvm] Why is my LVM Mirror performance so bad? Micky
2014-09-29 8:59 ` Zdenek Kabelac
2014-09-29 18:15 ` Linda A. Walsh
2014-09-30 3:27 ` Brassow Jonathan
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