LVM2 vs MDADM performance

Posted by archer on Server Fault See other posts from Server Fault or by archer
Published on 2010-04-19T07:10:29Z Indexed on 2010/04/19 7:14 UTC
Read the original article Hit count: 575

Filed under:

lvm

|

lvm2

|

mdadm

|

linux

I've used MDADM + LVM2 on many boxes for quite a while. MDADM was serving for both RAID0 and RAID1 arrays, while LVM2 where used for logical volumes on top of MDADM.

Recently I've found that LVM2 could be used w/o MDADM (thus minus one layer, as the result - less overhead) for both mirroring and stripping.

However, some guys claims that READ PERFORMANCE on LVM2 for mirrored array is not that fast as for LVM2 (linear) on top of MDADM (RAID1) as LVM2 does not read from 2+ devices at a time, but use 2nd and higher devices in case of 1st device failure. MDADM reads from 2 devices at a time (even in mirrored mode).

Who could confirm that?

© Server Fault or respective owner

Related posts about lvm

Unix LVM: how to resize root lvm

as seen on Server Fault - Search for 'Server Fault'
I took over a virtual server at work after a co-worker left. He, however, setup the server incorrectly at multiple stages and im cleaning them up as I run into them... Currently I realized that the file system is broken in half onto 2 logical volumes both at 50gb. One is mounted as the root directory… >>> More
RAID5 over LVM on Ubuntu Server 12.04.3

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I'm trying to create a RAID5 software array using LVM. I use VirtualBox as I'm only learning how LVM works. So I've created 4 virtual SCSI drives and then did the following: pvcreate /dev/sd[b-e] vgcreate /dev/sd[b-e] raid5_vg lvcreate --type raid5 -i 3 -L 1G -n raid_lv raid5_vg However, I get… >>> More
Preseeding Ubuntu partman recipe using LVM and RAID

as seen on Server Fault - Search for 'Server Fault'
I'm trying to preseed Ubuntu 12.04 server installation and created a recipe that would create RAID 1 on 2 drives and then partition that using LVM. Unfortunately partman complains when creating LVM volumes saying there no partitions in recipe that could be used with LVM (in console it complains about… >>> More
Restore data from overwritten LVM

as seen on Server Fault - Search for 'Server Fault'
I lost all of my data (8 TB) which I collected over the past few years yesterday because I made some seriuos mistakes during the remounting of my LVM. I run a XenServer5.6 installation with additional 4 harddisks for data storage. An LVM over those 4 HDDs was used to store all of my data. Yesterday… >>> More
how to multi-boot/upgrade linux from LVM-based partition

as seen on Super User - Search for 'Super User'
i currently have FC3 linux which installed itself on the hard disk using LVM partitioning, so it is basically all one big partition. i would like to try some other distributions and upgrade to something newer, but don't want to lose my current capabilities and data files, and i know nothing or less… >>> More

Related posts about lvm2

LVM2 vs MDADM performance

as seen on Server Fault - Search for 'Server Fault'
I've used MDADM + LVM2 on many boxes for quite a while. MDADM was serving for both RAID0 and RAID1 arrays, while LVM2 where used for logical volumes on top of MDADM. Recently I've found that LVM2 could be used w/o MDADM (thus minus one layer, as the result - less overhead) for both mirroring and… >>> More
Degraded RAID-5 array with lvm2 lost superblock and partition table

as seen on Server Fault - Search for 'Server Fault'
I have a RAID-5 array of 4x1TB hard disks with one lvm2 partition on Ubuntu Linux 10.04 LTS. One of the disks has failed. I have re-assembled the array without this failed disk but now mdadm --examine claims the array has no superblock and fdisk says it has no partition table. What can I do to recover… >>> More
List existing LVM2 tags

as seen on Server Fault - Search for 'Server Fault'
Adding tags to LVM volumes and showing volumes that possess that tag is easy and works like a charm; but somehow I can't find a way to list all tags in use, or to show tags that apply to a specific volume. lvdisplay -v doesn't give me details on tags, neither lvs seems to have any option for that… >>> More
LVM2 volume group lost

as seen on Server Fault - Search for 'Server Fault'
I updated one of my servers, but - although I took care not to modify - the volume groups on /dev/sdb1 were lost, although the physical volumes seem to be still there: [root@server ~]# pvscan PV /dev/sda2 VG VolGroup lvm2 [465,16 GiB / 0 free] PV /dev/sdb1 lvm2 [1… >>> More
Recover LVM2 volume group after one HDD failed

as seen on Super User - Search for 'Super User'
I had two HDDs, each one containing a LVM partition which formed a volume group. Then I had two LVs, one for my / directory and one for my /home/ directory. Yesterday where I had my / dir failed. I'm trying to recover at least my /home/ dir. What I've done so far: Boot a live system Extract LVM2… >>> More