[Linux-cluster] GFS limits: fs size, etc.

Ed L Cashin ecashin at coraid.com
Fri Sep 10 13:52:15 UTC 2004

Hi.  I'm trying to list all of the GFS limits that I can find.  The
one I'm most interested in is max filesystem size.  Here are the ones
I've found so far.

Is the theoretical limit on filesystem size 2^64 bytes or is there a
practical constraint?  I couldn't find that.

filesystem size:


file size: gfs_dinode has u64 di_size member, so

  16777216 TB is theoretical max file size

block size:

  gfs_mkfs manpage says min block size 512 bytes, max block size is
  the page size for the host

  Also, according to a comment at the top of gfs_ondisk.h, the
  de_rec_len member of gfs_dirent limits the FS block size to 64KB.

jounal size:

  gfs_mkfs manpage says min is 32MB  

extended attributes:

  max name length: 255 bytes
  max data length: 65535 bytes

  Ed L Cashin <ecashin at coraid.com>

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