Hi,

  We also found that using LVM gave a ~10% performance hist but we still 
use it as it is so flexable it solves otehr problems that override the loss.

Faye


On 10/03/11 19:50, Aaron van Meerten wrote:
> Another note with regards to LVM: with our infrastructure we did some basic IOZone and bonnie++ tests and discovered that use of LVM causes up to a 10% performance hit for I/O operations in relation to using a native partition table.  This convenience did not seem to be worth the hit in performance we found.
>
> -Aaron
>
>
> On Mar 10, 2011, at 1:48 PM, Konstantin Olchanski wrote:
>
>> On Thu, Mar 10, 2011 at 05:35:30AM -0500, Robert P. J. Day wrote:
>>>
>>>   first question -- is there any sane reason not to use LVM these
>>> days?  the manual opens (predictably) with showing the student how to
>>> allocate fixed partitions during the install, and leaves LVM setup for
>>> later in the week as an "advanced" topic.  i see it the other way
>>> around -- LVM should be the norm nowadays.
>>>
>>
>>
>> No reason to use LVM. The traditional "md" software raid is much simpler
>> and easier to manage (only one tool to learn - mdadm, compared
>> to the 100 lvm management programs). Historically, LVM is a knock-off
>> of XLV which was the companion partitionning tool to SGI's XFS filesystem.
>>
>>
>>>   thoughts?  i'll always allocate /boot as a regular partition but
>>> unless there are compelling reasons not to, i always recommend LVM as
>>> the standard.
>>
>>
>> Your /boot partition has to be mirrored across both of your system disks.
>> If it's only on one disk and it fails, you have an unbootable machine,
>> regardless of what tool you used (lvm or md).
>>
>> With "md" it is very simple, /dev/md0 is the system partition mirrored
>> across /dev/sda1 and /dev/sdb1, there is no need for separate /boot
>> partition, GRUB happily installs on both /dev/sda and /dev/sdb, and
>> your machine happily boots if either disk explodes.
>>
>> To do the same with LVM, you probably have to read a book and take
>> an advanced sysadmin class; and forget about getting it to actually
>> work without the help of this mailing list.
>>
>>
>> --
>> Konstantin Olchanski
>> Data Acquisition Systems: The Bytes Must Flow!
>> Email: olchansk-at-triumf-dot-ca
>> Snail mail: 4004 Wesbrook Mall, TRIUMF, Vancouver, B.C., V6T 2A3, Canada
>


-- 
---------------------------------------------------------
Faye Gibbins, Sys Admin.  GeoS KB.  Linux, Unix, Security
Beekeeper  - The Apiary Project, KB -   www.bees.ed.ac.uk
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