Side note:
In CentOS-6, I noticed a new option in lvresize / lvextend:
-r, --resizefs Resize underlying filesystem together with the logical volume using fsadm(8).
Nice. Two steps (lvresize and resize2fs) can now be combined into one! Works great.
But that has nothing to do with my question, just thought I'd share the discovery.
==
Anyway, here's the real issue with LVM, at least in CentOS-6:
[root@jttest ~]# df Filesystem 1K-blocks Used Available Use% Mounted on /dev/mapper/vg_main-lv_root 1548144 1548144 0 100% /
[root@jttest ~]# lvextend -L 2G /dev/vg_main/lv_root /etc/lvm/archive/.lvm_jttest.pp.local_5523_51321310: write error failed: No space left on device Volume group "vg_main" metadata archive failed. /etc/lvm/cache/.cache.tmp: write error failed: No space left on device
So I can't extend a logical volume if there's no space in /etc?
Granted, I only need to delete like 2k worth of files in the same logical volume as /etc to make the above work, but I don't recall lvresize or lvextend requiring space in /etc to do a resize. Has this always been the case? I don't have any 5.x servers handy to test this with. Can anyone verify?
If this is new, this seems less-than-ideal. /etc itself rarely fills up, so, in theory, I could make it its own LV, but that's even less ideal. For now, I'll stick to deleting just enough to do the extend/resize.
johnny
Am Montag, den 19.09.2011, 19:15 -0400 schrieb Johnny Tan:
Anyway, here's the real issue with LVM, at least in CentOS-6:
You would deal with the same issues in older lvm versions.
[root@jttest ~]# df Filesystem 1K-blocks Used Available Use% Mounted on /dev/mapper/vg_main-lv_root 1548144 1548144 0 100% /
Do i read that correctly and 1548144 1K Blocks are about 1,5G of Root File System? Please tell me you have a seperated /var for log files.
If not, for production use, install a tool which gives you a warning when reaching the 5% Level.
[root@jttest ~]# lvextend -L 2G /dev/vg_main/lv_root /etc/lvm/archive/.lvm_jttest.pp.local_5523_51321310: write error failed: No space left on device Volume group "vg_main" metadata archive failed. /etc/lvm/cache/.cache.tmp: write error failed: No space left on device
So I can't extend a logical volume if there's no space in /etc?
lvm tries to be helpfull if you ran into a power failure and can then recover due his tmp files in /etc.
Granted, I only need to delete like 2k worth of files in the same logical volume as /etc to make the above work, but I don't recall lvresize or lvextend requiring space in /etc to do a resize. Has this always been the case? I don't have any 5.x servers handy to test this with. Can anyone verify?
You will have the same problem, i think this procedure is the same in all lvm2 versions, which seems a long time now.
If this is new, this seems less-than-ideal. /etc itself rarely fills up, so, in theory, I could make it its own LV, but that's even less ideal. For now, I'll stick to deleting just enough to do the extend/resize.
This is why the older unix guys always seperate stuff from / which could fill up the root file system. ;)
On Mon, Sep 19, 2011 at 9:38 PM, Stefan Held obi@unixkiste.org wrote:
Am Montag, den 19.09.2011, 19:15 -0400 schrieb Johnny Tan:
Anyway, here's the real issue with LVM, at least in CentOS-6:
You would deal with the same issues in older lvm versions.
Thanks Stefan. I guess I just never noticed previously.
[root@jttest ~]# df Filesystem 1K-blocks Used Available Use% Mounted on /dev/mapper/vg_main-lv_root 1548144 1548144 0 100% /
Do i read that correctly and 1548144 1K Blocks are about 1,5G of Root File System? Please tell me you have a seperated /var for log files.
As evidenced by the hostname, this is a test VM solely for demonstration of this problem :-).
johnny
On Mon, Sep 19, 2011 at 07:15:09PM -0400, Johnny Tan wrote:
Anyway, here's the real issue with LVM, at least in CentOS-6:
[root@jttest ~]# df Filesystem 1K-blocks Used Available Use% Mounted on /dev/mapper/vg_main-lv_root 1548144 1548144 0 100% /
[root@jttest ~]# lvextend -L 2G /dev/vg_main/lv_root /etc/lvm/archive/.lvm_jttest.pp.local_5523_51321310: write error failed: No space left on device Volume group "vg_main" metadata archive failed. /etc/lvm/cache/.cache.tmp: write error failed: No space left on device
Many LVM modifications make a backup of the lvm metadata, which typically resides in /etc/lvm. You might try the -A n switch to disable the automatic backups (after strongly heeding the advice in man lvm; but as you said, on a test system, it's fine to play with). On a production system, if your / fills to 0 available blocks you've probably got bigger problems. :) So I imagine it's probably not a problem the LVM developers are too worried about (i.e., they may feel that the -A switch is sufficient to handle it).
--keith
On Mon, Sep 19, 2011 at 10:19 PM, Keith Keller kkeller@wombat.san-francisco.ca.us wrote:
On Mon, Sep 19, 2011 at 07:15:09PM -0400, Johnny Tan wrote:
Anyway, here's the real issue with LVM, at least in CentOS-6:
[root@jttest ~]# df Filesystem 1K-blocks Used Available Use% Mounted on /dev/mapper/vg_main-lv_root 1548144 1548144 0 100% /
[root@jttest ~]# lvextend -L 2G /dev/vg_main/lv_root /etc/lvm/archive/.lvm_jttest.pp.local_5523_51321310: write error failed: No space left on device Volume group "vg_main" metadata archive failed. /etc/lvm/cache/.cache.tmp: write error failed: No space left on device
Many LVM modifications make a backup of the lvm metadata, which typically resides in /etc/lvm. You might try the -A n switch to disable the automatic backups (after strongly heeding the advice in man lvm; but as you said, on a test system, it's fine to play with).
That did the trick:
[root@jttest~]# lvresize -L 2G /dev/vg_main/lv_root /etc/lvm/archive/.lvm_jttest.pp.local_1416_1029753972: write error failed: No space left on device Volume group "vg_main" metadata archive failed. /etc/lvm/cache/.cache.tmp: write error failed: No space left on device [root@jttest~]# lvresize -A n -L 2G /dev/vg_main/lv_root Extending logical volume lv_root to 2.00 GiB WARNING: This metadata update is NOT backed up Logical volume lv_root successfully resized /etc/lvm/cache/.cache.tmp: write error failed: No space left on device
(And the subsequent resize worked too.)
Thank you for pointing out the -A flag (missed the fine print of common options being in man lvm).
As you noted, I would probably never run into this situation in a non-testing environment and, if I did, would have much bigger problems. This probably explains why I never saw it previously. Good to know.
johnny
Johnny Tan wrote: <snip>
Anyway, here's the real issue with LVM, at least in CentOS-6:
[root@jttest ~]# df Filesystem 1K-blocks Used Available Use% Mounted on /dev/mapper/vg_main-lv_root 1548144 1548144 0 100% /
[root@jttest ~]# lvextend -L 2G /dev/vg_main/lv_root /etc/lvm/archive/.lvm_jttest.pp.local_5523_51321310: write error failed: No space left on device Volume group "vg_main" metadata archive failed. /etc/lvm/cache/.cache.tmp: write error failed: No space left on device
So I can't extend a logical volume if there's no space in /etc?
<snip> Um, just how do you have your system partitioned? I've never seen /etc on its own partition; it's on the same partition as /... and if so, and *that's* full, you've got a much bigger problem.
mark
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Johnny Tan -
Keith Keller -
m.roth＠5-cent.us -
Stefan Held