Re-create LVM

[zeland]

For software RAID, we just need to keep a backup of our RAID array config file. So, if we format and re-install the root partition, we can build the RAID array from the saved config file. Just wanted to know how do we (if possible) go about re-create logical volumes, keeping the data on it intact?


--== Anything can go wrong. It's just a matter of how far wrong it will go till people think its right. ==--

 

[ericbrunson]

LVM keeps a header on each of the physical volumes to reconstruct the volume group, then the database for the logical volumes is stored there.

For a disaster recovery plan you should just worry about backing up the data, then the actual media becomes unimportant. Unless you're doing something ill-advised like backing up the physical volumes as devices rather than the filesystems, you shouldn't really ever have to worry about how the LVM stores its data.

 

[zeland]

I see. It's the first time that I'm implementing LVM on our file server running Gentoo Linux. I was planning a change to FC4 as Gentoo has had an issue of slowing down to a crawl after a couple of weeks of uptime. So far it has happened twice in a strech of 4 months. I'm trying to avoid any extended down time as I usually only have Sundays to do such work and Backup & Restore usually take almost a whole day to complete. At least if I could avoid the restore part, could save me a good half day.


--== Anything can go wrong. It's just a matter of how far wrong it will go till people think its right. ==--

 

[ericbrunson]

LVM isn't designed to be fault tolerant, like a RAID array, it's more for ease of administration and flexibility. Put LVM on top of a raid array for fault tolerance, but backup the filesystems at the top layer for disaster recovery.

 

[marsd]

LVM does support data striping and mirroring and some other raid like features but Eric is mostly right IMO.
Nothing beats a good backup of the filesystems in question.

As far as your gentoo problems...This may be flamebait but
if you want to use FreeBSD, then use FreeBSD. Gentoo is not a replacement for FBSD and FBSD is not linux. Otherwise use a
time tested , user supported linux, like SuSE, debian, or FC.

 

[zeland]

As a matter of fact, I am using LVM on top of a 4x250GB RAID-5 array connected to an Adaptec 2410SA controller for quota management of our home, mail, projects and business documents folders. I had not planed to use Gentoo for my file server, but it was the only distro I had on hand that could support my 2410SA off the bat. FC3, Debian & SuSe could not detect my controller card during installation.


--== Anything can go wrong. It's just a matter of how far wrong it will go till people think its right. ==--