Stephan Austermuehle wrote:
>
> Hello,
>
> what is the absolut maximum storage capacity that can be managed on a
> single Linux 2.4 system with LVM?
man vgcreate
-s, --physicalextentsize PhysicalExtentSize[kKmMgGtT]
Sets the physical extent size on physical volumes of this
volume group.
A size suffix (k for kilobytes up to t for terabytes)
is optional,
megabytes is the default if no suffix is present. Values
can be from 8
KB to 16 GB in powers of 2. The default of 4 MB causes
maximum LV sizes
of ~256GB because as many as ~64k extents are supported
per LV. In case
larger maximum LV sizes are needed (later), you need to
set the PE size
to a larger value as well. Later changes of the PE size
in an existing
VG are not supported.
So, this means you can allocate
64k * 16G == 64*1024 * 16*1024*1024*1024 == 1125899906842624 bytes ==
1024Tera Bytes,
Hovever,
To limit kernel memory usage, there is a limit of 65536 physical
extents (PE)
per logical volume, so the PE size determines the maximum
logical volume size.
The default PE size of 4MB limits a single logical volume to
256GB (see the -s
option to raise that limit). There is also (as of Linux 2.4) a
kernel limita
tion of 2TB per block device.
So, this would mean 2TB pr. LV, but there can also be a number of LV's.
I dont remember how many, but proberly a power of 2, like 256 or 64k.
But wait, there is more...
You can have more than one VG system on your linux (no idea how many, i
have had 2)
So, all in all, i would asume you can have MANY TERABYTES. Possibly
Penta? bytes ?
How much space do you need anyway ?
JonB
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