Volume Shadow Copy For Linux? 300
An anonymous reader writes "I was asked to manage a number of Linux servers at work. I would like to use volume snapshots to improve my backup scripts and keep recent copies of data around for quick restore. I normally manage Windows servers and on those I would just use Microsoft's Volume Shadow Copy for this. I tried Linux LVM snapshots, but most of the servers I manage run regular partitions with ext3 file systems, so LVM snapshots will not work. I found some versioning file systems out there like ext3cow and Tux3. Those look interesting, but I need something I can use on my existing ext3 file systems. I also found the R1Soft Hot Copy command-line utility, but it does not yet support my older 2.4 Linux servers. What are you using to make snapshots on Linux?"
Rsync, dd (Score:1, Interesting)
Most people just use rsync for backups. LVM is a lower level then the file system... you create a storage pool and then create filesystems on top of that. If you really want to use LVM snapshots you would have to recreate your filesystems, which I gather you would like to avoid. There are lots of options for filesystems that include versioning in some form or another. If you do want to choose one of these filesystems, find the Wikipedia article for any filesystem and down at the bottom will be a list of filesystems you can explore. If you just want to snapshot the entire partition, you can remount it readonly and use dd to copy the block device to a file (this will take up space for every byte, including unused space unless you compress it). I congratulate you on the opportunity to work in a unix environment. Please don't get discouraged because it is different, it really isn't that hard to learn, and many people would say it's easer. Google and Wikipedia will be indispensable.
Re:no offense, but what a windows mentality (Score:5, Interesting)
There's a mix of humor and catty vitriol here all around, but here is something that addresses the serious point made in Grandparent's statement about it being a "Windows" way of thinking.
Take a look at Infrastructures.org [infrastructures.org] which describes a whole way of thinking about server reliability and configuration. Where I work we essentially use this approach. The fundamental concepts around this approach concentrate more on system configuration, ability to pick a random server and drop it out the window and have another one just like it online in moments. It's less about backups, and far more about a more comprehensive disaster recovery/prevention type of thing. The types of approaches described there are probably more easily implemented using Unix/Linux, but is probably also possible with Windows boxes.
Re:no offense, but what a windows mentality (Score:3, Interesting)
infrastructures.org looks interesting, but then I see they mention things like 'NetSaint' which was renamed to be Nagios about 7 years ago, and references to "LISA '98".
Some of this information looks old. Am I right? These days, shouldn't we be thinking more about virtualization and cloud infrastructure?
That said, they do touch upon many good ideas. It seems that many mid-sized shops do follow some similar ideas.
Re:hey retard: (Score:3, Interesting)
LVM snapshots suck because you can't store the snapshot data on the filesystem you're snapshotting. Sure, there's tons of ways to come up with extra space to store the snapshot data in, but they're all gigantic pains in the ass.
All it needs is the ability to exclude particular blocks from the snapshot, which should be a ridiculously easy option to implement for anyone who's worked on the snapshot code, and then people who aren't experts in kernel hacking can take care of the rest of the layers to make it a user-friendly operation, but nobody will do that because of hurf durfy crap that doesn't account for how people actually use computers.
Re:"does not yet support my older 2.4 Linux server (Score:3, Interesting)
Exactly, about 2 1/2 years ago I worked for a large company that everyone here has heard of that at the time was running ~4000 servers on a modified Redhat 6.2 image. There was a large code base that got lost sometime in the start-up phase of the mid 90s that was much easier to never touch the OS then to re-write the code.
Re:"does not yet support my older 2.4 Linux server (Score:3, Interesting)
Some of our systems still use token ring coax networks and OpenVMS servers.
The problem is that the fuckers just work... and keep on chugging along happily in the basement of the plant...