Just discovered that on CentOS 4.1 when you issue the command:
lvcreate -s -n temp -L2G /dev/vgname/lvname
to create a snapshot, you get the error message:
snapshot: Required device-mapper target(s) not detected in your kernel
I've checked and recheck my spelling and tried using the device created under /dev/mapper. I've tried it on both x86_64 and on i386. Works as expected under CentOS 3.5.
Any ideas what is going on?
Kirk Bocek wrote:
Just discovered that on CentOS 4.1 when you issue the command:
lvcreate -s -n temp -L2G /dev/vgname/lvname
to create a snapshot, you get the error message:
snapshot: Required device-mapper target(s) not detected in your kernel
I've checked and recheck my spelling and tried using the device created under /dev/mapper. I've tried it on both x86_64 and on i386. Works as expected under CentOS 3.5.
Any ideas what is going on?
CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
I had exactly the same errors when I was using release candidates of 4.0. 4.0 final fixed the problem.
I just tried it on 4.1 x86_64;
[root@services log]# lvcreate -s -n temp -L2G /dev/VolGroup00/tmplv Logical volume "temp" created
but when I tried to remove it, there was a problem;
lvremove: page allocation failure. order:0, mode:0xd0
Call Trace:<ffffffff801651b3>{__alloc_pages+709} <ffffffffa006464f>{:dm_mod:kcopyd_client_create+586} <ffffffffa00bc49d>{:dm_snapshot:snapshot_ctr+761} <ffffffffa005fce4>{:dm_mod:dm_table_add_target+328} <ffffffffa0061e7f>{:dm_mod:table_load+225} <ffffffffa0061d9e>{:dm_mod:table_load+0} <ffffffffa00627f2>{:dm_mod:ctl_ioctl+585} <ffffffff8019c22a>{sys_ioctl+1006} <ffffffff801108c6>{system_call+126} Mem-info: DMA per-cpu: cpu 0 hot: low 2, high 6, batch 1 cpu 0 cold: low 0, high 2, batch 1 Normal per-cpu: cpu 0 hot: low 32, high 96, batch 16 cpu 0 cold: low 0, high 32, batch 16 HighMem per-cpu: empty
Free pages: 11712kB (0kB HighMem) Active:48508 inactive:24962 dirty:80 writeback:0 unstable:0 free:2928 slab:30118 mapped:33239 pagetables:916 DMA free:11712kB min:20kB low:40kB high:60kB active:0kB inactive:0kB present:16384kB pages_scanned:199 all_unreclaimable? yes protections[]: 0 0 0 Normal free:0kB min:688kB low:1376kB high:2064kB active:194032kB inactive:99848kB present:507648kB pages_scanned:0 all_unreclaimable? no protections[]: 0 0 0 HighMem free:0kB min:128kB low:256kB high:384kB active:0kB inactive:0kB present:0kB pages_scanned:0 all_unreclaimable? no protections[]: 0 0 0 DMA: 4*4kB 2*8kB 6*16kB 2*32kB 4*64kB 2*128kB 1*256kB 1*512kB 0*1024kB 1*2048kB 2*4096kB = 11712kB Normal: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 0kB HighMem: empty Swap cache: add 67, delete 47, find 7/10, race 0+0 Free swap: 2096996kB 131008 pages of RAM 20213 reserved pages 36877 pages shared 20 pages swap cached device-mapper: Could not create kcopyd client device-mapper: error adding target to table
and 4.1 i386;
[root@inetmail ~]# lvcreate -s -n temp -L10m /dev/VolGroup00/usrlv Rounding up size to full physical extent 32.00 MB Logical volume "temp" created
[root@inetmail ~]# lvremove /dev/VolGroup00/temp Do you really want to remove active logical volume "temp"? [y/n]: y Logical volume "temp" successfully removed [root@inetmail ~]#
Hope this helps.
Bards1888 wrote:
I had exactly the same errors when I was using release candidates of 4.0. 4.0 final fixed the problem.
I just tried it on 4.1 x86_64;
[root@services log]# lvcreate -s -n temp -L2G /dev/VolGroup00/tmplv Logical volume "temp" created
but when I tried to remove it, there was a problem;
lvremove: page allocation failure. order:0, mode:0xd0
<snip>
Hope this helps.
Nope. No help at all. ;)
I've been using snapshots for as long as CentOS/Whitebox 3 have been around (just transitioned away from Whitebox). I would very much like to get it working on my 4.1 systems.
So you can create snapshots but not remove them under 4.1?
Kirk Bocek
Kirk Bocek wrote:
Bards1888 wrote:
I had exactly the same errors when I was using release candidates of 4.0. 4.0 final fixed the problem.
I just tried it on 4.1 x86_64;
[root@services log]# lvcreate -s -n temp -L2G /dev/VolGroup00/tmplv Logical volume "temp" created
but when I tried to remove it, there was a problem;
lvremove: page allocation failure. order:0, mode:0xd0
<snip>
Hope this helps.
Nope. No help at all. ;)
I've been using snapshots for as long as CentOS/Whitebox 3 have been around (just transitioned away from Whitebox). I would very much like to get it working on my 4.1 systems.
So you can create snapshots but not remove them under 4.1?
Kirk Bocek
CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
i386 was fine.
x86_64 created one ok but it could not be removed. I power cycled the box and then I was able to remove it.
On Sat, 2005-07-30 at 18:25 -0700, Kirk Bocek wrote:
Nope. No help at all. ;) I've been using snapshots for as long as CentOS/Whitebox 3 have been around (just transitioned away from Whitebox). I would very much like to get it working on my 4.1 systems. So you can create snapshots but not remove them under 4.1?
Kernel 2.6 with LVM2 (RHEL4) is very different than Kernel 2.4 with LVM (RHEL3). The device-mapper (DM) facilities provide snapshots, as well as software RAID-1 mirroring (instead of MD, which is also an option), resizing, etc...
Last time I checked, most of the LVM2/DM tools were getting there, as long as you didn't do more than one operation at a time (e.g., snapshot of a LVM2 RAID-1 mirror). If you did, that created a race condition.
I haven't messed with LVM2/DM since late last fall as a result.
On Saturday 30 July 2005 17.01, Kirk Bocek wrote:
Just discovered that on CentOS 4.1 when you issue the command:
lvcreate -s -n temp -L2G /dev/vgname/lvname
to create a snapshot, you get the error message:
snapshot: Required device-mapper target(s) not detected in your kernel
I think you need to do:
modprobe dm-snapshot
but I haven't tested it myself but almost the same thing happened to me when I tried to move a lv around (it then needs dm-mirror..)
good luck, Peter
I've checked and recheck my spelling and tried using the device created under /dev/mapper. I've tried it on both x86_64 and on i386. Works as expected under CentOS 3.5.
Any ideas what is going on?
Well thank you Peter. Thas was indeed the solution. A simple 'modprobe dm-snapshot' and now I can create snapshots.
This falls into the category of 'LVM1 to LVM2 Transition Gotcha'. Do you have any other 'gotchas' to share? I wonder why these modules aren't loaded when either an LVM device is detected or a command requiring them is run?
Kirk Bocek
Peter Kjellström wrote:
On Saturday 30 July 2005 17.01, Kirk Bocek wrote:
Just discovered that on CentOS 4.1 when you issue the command:
lvcreate -s -n temp -L2G /dev/vgname/lvname
to create a snapshot, you get the error message:
snapshot: Required device-mapper target(s) not detected in your kernel
I think you need to do:
modprobe dm-snapshot
but I haven't tested it myself but almost the same thing happened to me when I tried to move a lv around (it then needs dm-mirror..)
good luck, Peter
I've checked and recheck my spelling and tried using the device created under /dev/mapper. I've tried it on both x86_64 and on i386. Works as expected under CentOS 3.5.
Any ideas what is going on?
CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
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Bards1888 -
Bryan J. Smith -
Kirk Bocek -
Peter Kjellström