[linux-lvm] Problems with LVM

Heinz J . Mauelshagen mauelshagen at sistina.com
Sun Jul 13 15:26:01 UTC 2003


On Sun, Jul 13, 2003 at 11:27:43AM -0700, Petro wrote:
> On Sun, Jul 13, 2003 at 12:11:51PM +0200, Heinz J . Mauelshagen wrote:
> > Petro,
> > what's the lvcreate command line ?
> 
> lvcreate -L10G -n snap000 -s /dev/vg0 

Looks like another vmalloc bug :(

Kernel memory for snapshot exception tables gets allocated with vmalloc()
which shouldn't fail (presumably there's enough memory free,
which I assume in your case).

> 
> > (highmem may cause problems if you use the snapsho9t, creation should
> > work fine)
> 
> Is this highmem problem across all 2.4 kernels, or just 2.4.19+? The
> first report I've seen of it is with a 2.4.19 kernel. 

Didn't retest with kernel 2.4.21 yet.
The ones before had it AFAIK.

Regards,
Heinz    -- The LVM Guy --

> 
> > 
> > Regards,
> > Heinz    -- The LVM Guy --
> > 
> > On Fri, Jul 11, 2003 at 05:01:27PM -0700, Petro wrote:
> > > Hello again. 
> > > 
> > > I'm having a problem with LVM, and I'm really, really hoping you won't
> > > tell me it's because of:
> > > 
> > > # CONFIG_NOHIGHMEM is not set
> > > CONFIG_HIGHMEM4G=y
> > > # CONFIG_HIGHMEM64G is not set
> > > CONFIG_HIGHMEM=y
> > > CONFIG_HIGHIO=y
> > > 
> > > (linux kernel 2.4.21, lvm 1.0.7 stuff installed)  
> > > 
> > > I've got 8 boxes with 4 gig of memory, and 6 200 gig drives in a raid 0 
> > > setup, and I need to use LVM+Snapshots. 
> > > 
> > > I can setup and create a 1.09T logical volume, but when I go to create a
> > > snaphot, I get: 
> > > 
> > > lvcreate -- INFO: using default snapshot chunk size of 64 KB for "/dev/vg0/test"
> > > lvcreate -- ERROR "Cannot allocate memory" creating VGDA for "/dev/vg0/test" in kernel
> > > 
> > > Now, in reading past posts there is some talk of how having "high
> > > memory" turned on will cause problems with snapshots. 
> > > 
> > > The problem is that on these machines I *need* 4 gig of memory, and I
> > > *need* snapshots. 
> > > 
> > > Help? 
> > > 
> > > 
> > > --- Physical volume ---
> > > PV Name               /dev/sda
> > > VG Name               vg0
> > > PV Size               1.09 TB [2344319232 secs] / NOT usable 32.31 MB [LVM: 267 KB]
> > > PV#                   1
> > > PV Status             available
> > > Allocatable           yes
> > > Cur LV                1
> > > PE Size (KByte)       32768
> > > Total PE              35770
> > > Free PE               570
> > > Allocated PE          35200
> > > PV UUID               LyEPH1-pq2I-D022-v5c9-98rp-n7Ff-4LnNKL
> > > 
> > > --- Volume group ---
> > > VG Name               vg0
> > > VG Access             read/write
> > > VG Status             available/resizable
> > > VG #                  0
> > > MAX LV                256
> > > Cur LV                1
> > > Open LV               1
> > > MAX LV Size           2 TB
> > > Max PV                256
> > > Cur PV                1
> > > Act PV                1
> > > VG Size               1.09 TB
> > > PE Size               32 MB
> > > Total PE              35770
> > > Alloc PE / Size       36032 / 1.10 TB
> > > Free  PE / Size       4294967034 / 131071.99 TB
> > > VG UUID               KciSkB-xbr8-22RM-zmke-6A69-6BEM-xLWMzv
> > > 
> > > --- Logical volume ---
> > > LV Name                /dev/vg0/lv0
> > > VG Name                vg0
> > > LV Write Access        read/write
> > > LV Status              available
> > > LV #                   1
> > > # open                 1
> > > LV Size                1.07 TB
> > > Current LE             35200
> > > Allocated LE           35200
> > > Allocation             next free
> > > Read ahead sectors     1024
> > > Block device           58:0
> > > 
> > > 
> > >    procs                      memory    swap          io     system         cpu
> > >  r  b  w   swpd   free   buff  cache  si  so    bi    bo   in    cs  us  sy  id
> > >  0  0  0      0 3949704   1648  26104   0   0     3     2   27     5   0   0 100
> > > 
> > > 
> > > -- 
> > > "On two occasions, I have been asked [by members of Parliament], 'Pray, 
> > > Mr. Babbage, if you put into the machine wrong figures, will the right 
> > > answers come out?' I am not able to rightly apprehend the kind of confusion 
> > > of ideas that could provoke such a question." -- Charles Babbage 
> > > 
> > > _______________________________________________
> > > linux-lvm mailing list
> > > linux-lvm at sistina.com
> > > http://lists.sistina.com/mailman/listinfo/linux-lvm
> > > read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
> > 
> > *** Software bugs are stupid.
> >     Nevertheless it needs not so stupid people to solve them ***
> > 
> > _______________________________________________
> > linux-lvm mailing list
> > linux-lvm at sistina.com
> > http://lists.sistina.com/mailman/listinfo/linux-lvm
> > read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
> 
> -- 
> "On two occasions, I have been asked [by members of Parliament], 'Pray, 
> Mr. Babbage, if you put into the machine wrong figures, will the right 
> answers come out?' I am not able to rightly apprehend the kind of confusion 
> of ideas that could provoke such a question." -- Charles Babbage 
> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm at sistina.com
> http://lists.sistina.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

*** Software bugs are stupid.
    Nevertheless it needs not so stupid people to solve them ***

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Heinz Mauelshagen                                 Sistina Software Inc.
Senior Consultant/Developer                       Am Sonnenhang 11
                                                  56242 Marienrachdorf
                                                  Germany
Mauelshagen at Sistina.com                           +49 2626 141200
                                                       FAX 924446
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