Linked by Thom Holwerda on Sun 18th May 2008 15:32 UTC, submitted by sjvn
Sun Solaris, OpenSolaris It seems like we're really on the subject of filesystems and related technology the past few days. We had an interview with the man behind BeServed, an item on WinFS' current status, and now we - possibly - have news on ZFS coming to Linux. Possibly, because it's all speculation from here on out.
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RE[5]: I use ZFS on 1GB RAM
by MattPie on Mon 19th May 2008 20:07 UTC in reply to "RE[4]: I use ZFS on 1GB RAM"
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hmm....I have to read up on LVM again. I was sure that the lvmove command basically moved all files from a specific pv and moved the data to the space available in the vg. If thats not the case, then yeah, I guess you were kinda screwed. :/

You're correct. I suspect the original poster made a VG with 3 disks, and an LV that took up all the space in that VG. In that situation, you'd have to:
- Use 'resize2fs' (assuming ext2/3) to shrink the file system to fit on the two remaining disks.
- Use 'lvreduce' to shrink the LV to fit on the remaining disks. Make sure the file system is smaller than the LV!
- Use 'pvmove' to move the extents off the PV to be removed.
- Use 'vgreduce' to remove the PV from the VG.

The lesson here is to only allocate space to a volume when you need it. Don't just make a giant LV that takes up all your space. It's a lot easier to expand a volume than it is to shrink it. You can even expand a ext3 file system while it's on-line.

Also, ZFS is fantastic. I have a few Sun T-series boxes and it's just so damn easy to use.

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