tar system backup...best pack/unpack order?

mikeybsae · 03-31-2004, 05:10 PM

I am writing a script to backup my entire filesystem with tar. My entire system is on one / partition. What I would like to do is create a tar file of the entire system and then write unpack it to a different partition to create a copy of my system. I did this and changed fstab and lilo.conf, rewrote the boot record of the partition with lilo, and it booted and ran fine, but it was slow. I am thinking that it might be slow due to the order in which I packed and unpacked the old system. I had some problems figuring out what parts of the filesystem could(should) be moved, so ended up making individual tar files of all the directories below /. Then unpacked these individually onto a newly formatted and mounted ext3 partition.

I am running Archlinux with kernel 2.6.4 and the ext3 filesystem. I didn't move /dev, /sys, /proc, /mnt, /lost+found, /tmp, /var/cache, and /usr/src. But created new empty directories for all of them with the proper permissions on the new partition. I can't recall the order in which I unpacked everything, it was very haphazard.

So my question is what would be the best order to tar up my system? or is this even an issue? I know that tar can preferentially pack certain folders/files first in the file it creates, and I am thinking this is the way to go. So if someone can tell me what sections of the filesystem benefit the most by being near the front of the partition that would be great.

I would think that I should get around the same or better performance with the new partition I am using since it is the same size as the old and closer to the front of the disc.

mikeyb

jailbait · 03-31-2004, 09:22 PM

"So my question is what would be the best order to tar up my system? or is this even an issue?"

I use tar to back up my entire system to CD-ROM once a week. The process of packing large tar files is slow and has always been slow. I doubt that the file order has anything to do with it.

"I would think that I should get around the same or better performance with the new partition I am using since it is the same size as the old and closer to the front of the disc."

Actually, the fastest partition is the one nearest the center of the disc. It is a question of minimizing disc arm movement.

"So if someone can tell me what sections of the filesystem benefit the most by being near the front of the partition that would be great."

The files are not necessarily in the same physical order as creation order. Nor are files necessarily loaded into a partition contiguously. In fact you have absolutely no way to control where a file resides physically within a partition.

___________________________________
Be prepared. Create a LifeBoat CD.
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Steve Stites

mikeybsae · 08-19-2004, 07:27 PM

so is the stuff mentioned in this article, about optimizing/increasing performance not true?

http://www.user.dccnet.com/jonleblan...dual_boot.html

this web page went away for a while, which is why it has taken me so long to get back to this post. I wanted to include it because it was what prompted my questions to begin with. I hope someone will be interested in clearing this up for me.

jailbait · 08-20-2004, 11:12 AM

"so is the stuff mentioned in this article, about optimizing/increasing performance not true?"

The article is true for Windows. It is irrelevent for Linux.

___________________________________
Be prepared. Create a LifeBoat CD.
http://users.rcn.com/srstites/LifeBo...home.page.html

Steve Stites