Re: raid10 and lvm problem on new lenny install
On Sat, Mar 19, 2011 at 10:02:24PM -0400, Jim Green wrote:
> this is what I have from fdisk -l, I have lvm on /dev/md1, md1 is a
> raid10 array with 4x2T drives.
> Disk /dev/md1: 4000.5 GB, 4000525058048 bytes
> 2 heads, 4 sectors/track, 976690688 cylinders
> Units = cylinders of 8 * 512 = 4096 bytes
> Sector size (logical/physical): 512 bytes / 512 bytes
> I/O size (minimum/optimal): 524288 bytes / 2097152 bytes
> Disk identifier: 0x00000000
Note that 4000525058048 != 4 x 2^40 (4398046511104)
> this is what I have from pvdisplay
> --- Physical volume ---
> PV Name /dev/md1
> VG Name 2600k
> PV Size 3.64 TiB / not usable 0
> Allocatable yes
> PE Size 4.00 MiB
> Total PE 953799
> Free PE 831052
> Allocated PE 122747
> PV UUID WUpkTR-xyCK-HGOc-Hk7Q-OfBp-Mqsz-GubCy7
2^40 = 1099511627776
4000525058048 / 1099511627776 = 3.6384563446044921875 ~= 3.64
> I don't know why I only have a 3.64T pv size, it should be 4T I think,
> in the installation of lenny i use ext3 for all the partitions,
> also I set the unused space for each partition as 1%.
>
> Thank you if you have an explanation or if you have ways to reclaim
> the 0.36 T from my arrays.
The difference is between what vendors use to describe their drives (TB,
meaning trillions of bytes) and what sane computer systems use (TiB,
meaning 2^40 bytes).
> Jim
--Greg
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