Share your knowledge at the LQ Wiki.
Go Back > Forums > Linux Forums > Linux - Virtualization and Cloud
User Name
Linux - Virtualization and Cloud This forum is for the discussion of all topics relating to Linux Virtualization and Linux Cloud platforms. Xen, KVM, OpenVZ, VirtualBox, VMware, Linux-VServer and all other Linux Virtualization platforms are welcome. OpenStack, CloudStack, ownCloud, Cloud Foundry, Eucalyptus, Nimbus, OpenNebula and all other Linux Cloud platforms are welcome. Note that questions relating solely to non-Linux OS's should be asked in the General forum.


  Search this Thread
Old 12-07-2011, 08:06 AM   #1
Registered: Oct 2006
Distribution: Debian, OpenBSD, FreeBSD
Posts: 31

Rep: Reputation: 0
Encrypted LVM on a SAN with SSD fast cache drives failure


We have just purchased a new EMC SAN with SSD fast-cache ( ).
I have set up a VM running database server with Postgres 8.4 on Debian squeeze 64bit with encrypted LVM partition and a second VM with unencrypted LVM, same spec otherwise. I was trying to determine how much impact the encryption will have on performance. The first results showed much slower performance of the encrypted one, but consecutive querries results were much better, encryption seemed to have minimal impact on the query speed.
The query used LIKE clause to search for records containing a string
| Encrypted | Not encrypted
Selecting 78`786 records | 2 m 32s | 13s
Selecting 18`408`379 records | 13 s | 15s

total record count :30`016`693
I gathered this would be due to fast cache being used. During the second query the table was already moved to fast cache. However, when I was trying to run another query, updating a few milion records the encrypted server crashed. On VCenter I saw an alert "Alarm 'Virtual machine cpu usage' changed from Green to Yellow" and the machine threw some kernel panic messages on screen and froze. The other VM using unencrypted file system runs just fine.

The server was freshly installed with default debian settings, I just tuned Postgres a bit ( or maybe a lot, my databases are from 50 to 120 Gig each, so it would not run on default settings ).

Anyone have experience with running encrypted LVM on SAN with Fast-cache ? I'm a bit concerned with the result of my tests so far, don't want to store data on a server that's not reliable. Not sure what caused the issue, but it's kind of scary it happened.


Last edited by Ladowny; 12-07-2011 at 08:09 AM.


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
ssd drives tutorial portia Linux - Hardware 2 11-17-2011 09:07 AM
[SOLVED] LVM ontop of encrypted file system - 2 drives BashTin Slackware 11 10-19-2011 03:21 PM
Recover Raid+LVM on non system drives after system failure spindley Linux - General 4 01-19-2011 05:18 PM
SSD drives McDivot Linux - Newbie 2 09-28-2010 06:00 PM
poormans fast SSD boot? netsurf Linux - Hardware 2 07-06-2009 01:33 PM > Forums > Linux Forums > Linux - Virtualization and Cloud

All times are GMT -5. The time now is 03:04 AM.

Main Menu
Write for LQ is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Open Source Consulting | Domain Registration