Large file system oddities

Large file system oddities

[Lukas Hejtmanek]

Hello,

I use vanilla kernel 2.6.13.4 on Pentium 4 with EM64T extensions in x86_64 mode.

I have 3.5TB partition formated as XFS.

This is from dmesg:
scsi2 : Adaptec AIC79XX PCI-X SCSI HBA DRIVER, Rev 1.3.11
        <Adaptec 39320A Ultra320 SCSI adapter>
        aic7902: Ultra320 Wide Channel A, SCSI Id=7, PCI-X 101-133Mhz, 512 SCBs

(scsi2:A:0): 160.000MB/s transfers (80.000MHz DT, 16bit)
  Vendor: SB-3163S  Model: Volume Set # 00   Rev: R001
  Type:   Direct-Access                      ANSI SCSI revision: 03
scsi2:A:0:0: Tagged Queuing enabled.  Depth 32
SCSI device sdc: 854676032 4096-byte hdwr sectors (3500753 MB)
SCSI device sdc: drive cache: write back
SCSI device sdc: 854676032 4096-byte hdwr sectors (3500753 MB)
SCSI device sdc: drive cache: write back
 sdc: unknown partition table


Using fdisk I made one big partition accross whole disk:

fdisk /dev/sdc
Note: sector size is 4096 (not 512)

The number of cylinders for this disk is set to 53201.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
   (e.g., DOS FDISK, OS/2 FDISK)

Command (m for help): p

Disk /dev/sdc: 3500.7 GB, 3500753027072 bytes
255 heads, 63 sectors/track, 53201 cylinders
Units = cylinders of 16065 * 4096 = 65802240 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdc1               1       53201  3418696008   83  Linux

However, cat /proc/partitions produces:
# cat /proc/partitions 
major minor  #blocks  name

   8     0  244198584 sda
   8     1   39062016 sda1
   8     2    3903795 sda2
   8     3  201230190 sda3
   8    32 3418704128 sdc
   8    33 1271212360 sdc1

I made XFS file system on it:
# mkfs.xfs -f -s size=4096 -d su=65536,sw=7 /dev/sdc1

mounted partition results in:
# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sdc1             1.2T  332G  882G  28% /mnt/export1


So what's wrong? Or am I something missing?


-- 
Lukáš Hejtmánek

Re: Large file system oddities

[Nathan Scott]

On Thu, Nov 03, 2005 at 08:03:34PM +0100, Lukas Hejtmanek wrote:
> Hello,
> 
> I use vanilla kernel 2.6.13.4 on Pentium 4 with EM64T extensions in x86_64 mode.
> 
> I have 3.5TB partition formated as XFS.

Looks like you actually ended up with a 1.2TB partition formatted
as XFS on a 3.5TB device...

> Using fdisk I made one big partition accross whole disk:

Why?  Just use /dev/sdc directly, and you'll avoid the 32 bit
problems fdisk (or the default partition table type, I can't
remember which it is now) evidently has.

>    Device Boot      Start         End      Blocks   Id  System
> /dev/sdc1               1       53201  3418696008   83  Linux

> # cat /proc/partitions 
>    8    32 3418704128 sdc
>    8    33 1271212360 sdc1

Yes, there's your problem.

> I made XFS file system on it:
> # mkfs.xfs -f -s size=4096 -d su=65536,sw=7 /dev/sdc1

mkfs.xfs is just using the information that its given from the
kernel, which is the second /proc/partitions line above.

> So what's wrong? Or am I something missing?

Try without the partition, looks like that'll work.

cheers.

-- 
Nathan

Re: Large file system oddities

[Lukas Hejtmanek]

On Fri, Nov 04, 2005 at 08:19:59AM +1100, Nathan Scott wrote:
> Why?  Just use /dev/sdc directly, and you'll avoid the 32 bit
> problems fdisk (or the default partition table type, I can't
> remember which it is now) evidently has.
> 
> Try without the partition, looks like that'll work.

Yes, this one works ok. I can see 3.2TB of free space. Thanks.

-- 
Lukáš Hejtmánek