lvscan and df result differs
I have just installed lvm on my debian testing server.
I have finally managed to create a PV on a maxtor 120G disk, the 'pvcreate' command complained about a partitiontable being present even if there is no table there.
--8<--
server:~# pvcreate --version pvcreate: Logical Volume Manager 1.0.4 Heinz Mauelshagen, Sistina Software 02/05/2002 (IOP 10) --8<-- I managed to get around that by using a v2 lvm command. Is there a bug in 1.0.x's pvcreate?
I have also managed to create a VG a and a LV and that seems to work. I have formatted the LV with ext3 and now the strange thing is that lvscan reports:
--8<--
server:~# lvscan lvscan -- ACTIVE "/dev/vg/lg" [114.49 GB] lvscan -- 1 logical volumes with 114.49 GB total in 1 volume group lvscan -- 1 active logical volumes --8<-- But when using the filesystem df reports: --8<-- Filesystem Size Used Avail Use% Mounted on /dev/hde1 123GB 121GB 2.4GB 99% /store /dev/vg/lg 122GB 121GB 0 100% /store2 --8<--
/dev/hde1 is also a 120G disk but with resierfs, ext3 takeing up more size is probably normal. But the actual size on the lvm is 122G and as you can see I can fit 121G on the disk, so why is lvscan reporting ~115G? Can i safetly use my lvm setup without running the risk of losing data?
Thanks,
/Magnus
Quoted 8 lines · Magnus Sandberg
I have just installed lvm on my debian testing server.
I have finally managed to create a PV on a maxtor 120G disk, the 'pvcreate' command complained about a partitiontable being present even if there is no table there.
--8<--
Quoted 6 lines
server:~# pvcreate --version pvcreate: Logical Volume Manager 1.0.4 Heinz Mauelshagen, Sistina Software 02/05/2002 (IOP 10) --8<-- I managed to get around that by using a v2 lvm command. Is there a bug in 1.0.x's pvcreate?
Did you zero the partition table?
i.e. "dd if=/dev/zero of=/dev/YourWholeDisk count=1 bs=512"
v1 "pvcreate /dev/YourWholeDisk" should work fine then.
Quoted 17 lines
I have also managed to create a VG a and a LV and that seems to work. I have formatted the LV with ext3 and now the strange thing is that lvscan reports:
--8<--server:~# lvscan lvscan -- ACTIVE "/dev/vg/lg" [114.49 GB] lvscan -- 1 logical volumes with 114.49 GB total in 1 volume group lvscan -- 1 active logical volumes --8<-- But when using the filesystem df reports: --8<-- Filesystem Size Used Avail Use% Mounted on /dev/hde1 123GB 121GB 2.4GB 99% /store /dev/vg/lg 122GB 121GB 0 100% /store2 --8<--
Quoted 6 lines
/dev/hde1is also a 120G disk but with resierfs, ext3 takeing up more size is probably normal. But the actual size on the lvm is 122G and as you can see I can fit 121G on the disk, so why is lvscan reporting ~115G? Can i safetly use my lvm setup without running the risk of losing data?
Can't reproduce that with df 4.1 here :(
That's probably just the old divide by 1k or 1024 thing.
What does "df -k" say and how does it compare to the lvscan output?
Quoted 12 lines
Thanks,
/Magnus
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Signature · 15 lines
Regards,
Heinz -- The LVM Guy --
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Nevertheless it needs not so stupid people to solve them ***
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=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-Quoted 6 lines · Heinz J . Mauelshagen
On Sun, Oct 27, 2002 at 01:30:01AM +0200, Magnus Sandberg wrote:
Did you zero the partition table?
i.e. "dd if=/dev/zero of=/dev/YourWholeDisk count=1 bs=512"v1 "pvcreate
/dev/YourWholeDisk" should work fine then.
Yes I did, several times, I even rebooted to make sure the table was reread.
Quoted 9 lines
Quoted 6 lines
/dev/hde1is also a 120G disk but with resierfs, ext3 takeing up more size is probably normal. But the actual size on the lvm is 122G and as you can see I can fit 121G on the disk, so why is lvscan reporting ~115G? Can i safetly use my lvm setup without running the risk of losing data?Can't reproduce that with df 4.1 here :(
That's probably just the old divide by 1k or 1024 thing.
Yes I suspected that but it stills scares me tad.
Quoted 1 line
What does "df -k" say and how does it compare to the lvscan output?
I'm using df 4.5.2, and df -k says:
Filesystem 1K-blocks Used Available Use% Mounted on/dev/vg/lg 118169924 117732724 0 100% /store2
and if using lvscan I get:
114.49*1000*1000 = 114490000
114.49*1024*1024 = 120051466,24
so with a few % off for the filesystem info it looks ok, But why is df using Size and Used info from the filesystem and the Available ans Use% info from the lvm-Volume?
/Magnus
Signature · 1 line
Magnus Sandberg <[email protected]>
Also don't forget lvm first takes off a little bit of your disk for its own use then it rounds the disk to your extent size, one of your extents is also reserved for future lvm use, so if you use an extent size of 4 meg 4.3-8.29 (approx) could be "missing" from your disk.
James