Trying to mount 13 Tb disk on RedHat system.

Fri Aug 14 12:22:22 UTC 2009

On Aug 14, 2009, at 4:50 AM, Nigel Wade wrote:

> Margaret Doll wrote:
>> We got to create the 13 Tb partition on the  aux  disk on the  
>> RedHat system by using parted, but then mkfs.ext3 doesn't work on  
>> any partition larger than 2 Tb.
>
> It should do. I have 6 and 7.8TB filesystems. What version of RH are  
> you running? I suppose there may be limitations on some of the  
> kernels, I am running 64bit RHEL 4. However, I think there is  
> limitation of 8TB for ext2/3 on systems which have a max. block/page  
> size of 4kb. You need 8kb blocks/pages to get to 16TB, or a  
> different filesystem type and it's unlikely your system can handle  
> that. Do you know what the max. page size if for your system?

How would I find this?
>
>> If we split the aux disk into 2 Tb partitions, I understand from http://www.linuxnix.com/2009/04/logical-volume-manager-lvm-in-redhat.html
>> that we use fdisk to  change the partition type to  83 Linux LVM.   
>> Unfortunately fdisk will only see the first 2 Tb partition, so we  
>> can't create a LVM
>> of the partitions.
>
> If you want to go this way create individual LUNs on your RAID.  
> There is nothing to be gained by partitioning the RAID. You can join  
> the LUNs using LVM. That would enable you to create an LVM of 13TB,  
> but you've gained nothing over using the bare device. You don't need  
> a partition table on a device, you can create a filesystem on the  
> entire device, /dev/sdc for example, rather than /dev/sdc1 etc.

Using parted, I think we did create and ext3 filesystem on the entire  
disk.
>
>> We went back to parted and created one 13 Tb partition.  Then  
>> inside  parted, we used
>> mkfs 0 ext3
>> The program said  that ext3  was not supported in this version of  
>> parted, but ext2 was.  I oked, ext2.
>> Inside parted
>> (parted) print
>> Model: IFT A16F-G2430 (scsi)
>> Disk /dev/sdc: 13.0TB
>> Sector size (logical/physical): 512B/512B
>> Partition Table: gpt
>> Number  Start   End     Size    File system  Name     Flags
>> 1      17.4kB  13.0TB  13.0TB  ext3         primary
>> the partition is  labeled as a ext3 file system.
>> Our 13 Tb partition was added to /etc/fstab as a ext3  filesystem  
>> and mounted on  the system.
>> "df -h" though lists it as a 1.8 Tb system.
>> /dev/sdc1             1.8T  196M  1.7T   1% /m3team
>
>
> Did you actually create a filesystem on that 13TB partition? Or did  
> you just use the filesystem which you had already created previously  
> when the partition was only 2TB? I'd be interested to know what mkfs  
> said when you asked it to create a 13TB filesystem, for example what  
> block size did it set.
>
> What does 'dumpe2fs /dev/sdc1' show?
dumpe2fs /dev/sdc1 > dump.rpt

Where dump.rpt shows

Filesystem volume name:   <none>
Last mounted on:          <not available>
Filesystem UUID:          2e6d48bb-5cde-4be0-af94-edf95ad64801
Filesystem magic number:  0xEF53
Filesystem revision #:    1 (dynamic)
Filesystem features:      has_journal resize_inode dir_index filetype  
needs_recovery sparse_super large_file
Default mount options:    (none)
Filesystem state:         clean
Errors behavior:          Continue
Filesystem OS type:       Linux
Inode count:              244154368
Block count:              488281245
Reserved block count:     24414062
Free blocks:              480569334
Free inodes:              244154357
First block:              0
Block size:               4096
Fragment size:            4096
Reserved GDT blocks:      907
Blocks per group:         32768
Fragments per group:      32768
Inodes per group:         16384
Inode blocks per group:   512
Filesystem created:       Thu Aug 13 15:26:09 2009
Last mount time:          Thu Aug 13 15:59:28 2009
Last write time:          Thu Aug 13 15:59:28 2009
Mount count:              1
Maximum mount count:      33
Last checked:             Thu Aug 13 15:26:09 2009
Check interval:           15552000 (6 months)
Next check after:         Tue Feb  9 14:26:09 2010
Reserved blocks uid:      0 (user root)
Reserved blocks gid:      0 (group root)
First inode:              11
Inode size:               128
Journal inode:            8
Default directory hash:   tea
Directory Hash Seed:      149a19fb-3302-49ff-8314-3a02abd591d1
Journal backup:           inode blocks
Journal size:             128M

Group 0: (Blocks 0-32767)
   Primary superblock at 0, Group descriptors at 1-117
...
...

Group 14900: (Blocks 488243200-488275967)
   Block bitmap at 488243200 (+0), Inode bitmap at 488243201 (+1)
   Inode table at 488243202-488243713 (+2)
   32254 free blocks, 16384 free inodes, 0 directories
   Free blocks: 488243714-488275967
   Free inodes: 244121601-244137984
Group 14901: (Blocks 488275968-488281244)
   Block bitmap at 488275968 (+0), Inode bitmap at 488275969 (+1)
   Inode table at 488275970-488276481 (+2)
   4763 free blocks, 16384 free inodes, 0 directories
   Free blocks: 488276482-488281244
   Free inodes: 244137985-244154368

>
> -- 
> Nigel Wade, System Administrator, Space Plasma Physics Group,
>            University of Leicester, Leicester, LE1 7RH, UK
> E-mail :    nmw at ion.le.ac.uk
> Phone :     +44 (0)116 2523548, Fax : +44 (0)116 2523555
>
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