Max. Filesystem Size under AIX 4.1.4

Max. Filesystem Size under AIX 4.1.4

Post by Thorsten Coorde » Tue, 05 Nov 1996 04:00:00



Hi,

who knows the maximal size of the largest filesystem I can create under
AIX 4.1.4? We don't have any 4.1.x manuals at all, so please mail the
answer to me.

Thanks TC
--
Thorsten Coordes
ZARM - University of Bremen     Tel.:   +49 - 421 - 218 - 4330
Am Fallturm                     Fax:    +49 - 421 - 218 - 2521

 
 
 

Max. Filesystem Size under AIX 4.1.4

Post by H.G. Borrma » Tue, 12 Nov 1996 04:00:00


: Hi,

: who knows the maximal size of the largest filesystem I can create under
: AIX 4.1.4? We don't have any 4.1.x manuals at all, so please mail the
: answer to me.

: Thanks TC
: --
: Thorsten Coordes
: ZARM - University of Bremen   Tel.:   +49 - 421 - 218 - 4330
: Am Fallturm                   Fax:    +49 - 421 - 218 - 2521

From Infoexplorer:

Maximum Journaled File System Size
The maximum JFS size is a function of the following three variables, which are
set when the file system is created:

     Logical partition size of the volume group
     Fragment size
     Number of i-nodes.

The Logical Volume Manager (LVM) limits a volume group to 32 physical volumes
and restricts a physical volume to 1016 logical partitions. This means that the maximum file system size as a function of volume group geometry is as follows:

32 x 1016 x PartitionSize

The fragment size limits the JFS size due to addressability constraints. Each
fragment within a file system must be addressable by a 28-bit value. This means that the maximum file system size as a function of fragment size is as follows:

228 x FragmentSize

Journaled file systems are also restricted to 224 i-nodes. This limitation
yields the following maximum file system size:

number of bytes per i-node (NBPI) x 224

The following table summarizes the restrictions on journaled file system size:
NBPI Ratio      Fragment Size           Partition Size  Maximum File System Size
                (bytes)                 (Megabytes)     (Gigabytes)
  512           512, 1024, 2048, 4096   >= 2          8
  1024          512, 1024, 2048, 4096   >= 2         16
  2048          512, 1024, 2048, 4096   >= 2         32
  4096          512,1024, 2048, 4096    >= 4         64

Hope that helps
HGB

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Max. Filesystem Size under AIX 4.1.4

Post by Tom Weav » Wed, 13 Nov 1996 04:00:00




>The fragment size limits the JFS size due to addressability constraints. Each
>fragment within a file system must be addressable by a 28-bit value. This means that the maximum file system size as a function of fragment size is as follows:

>228 x FragmentSize

 ^^^

This should be 2^28 - "two to the 28th power" - or 2**28 for FORTRAN types.

Quote:

>Journaled file systems are also restricted to 224 i-nodes. This limitation
>yields the following maximum file system size:

>number of bytes per i-node (NBPI) x 224

                                     ^^^

This should be 2^24 - "two to the 24th power" - 16 meg.

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