Lin Shen (lshen) wrote:
-----Original Message-----
From: Nathaniel Rutman [mailto:[EMAIL PROTECTED]
Sent: Wednesday, February 07, 2007 12:22 PM
To: Lin Shen (lshen)
Cc: [email protected]
Subject: Re: [Lustre-discuss] disk space needed to run MDS
Lin Shen (lshen) wrote:
-----Original Message-----
From: Andreas Dilger [mailto:[EMAIL PROTECTED]
Sent: Monday, February 05, 2007 9:03 AM
To: Lin Shen (lshen)
Cc: [email protected]
Subject: Re: [Lustre-discuss] disk space needed to run MDS
On Feb 02, 2007 10:25 -0800, Lin Shen (lshen) wrote:
Could you explain a bit more how the number 400M was
decided? Ext3
itself won't need that much disk space, right? Also, is
this number
related to the total capacity of the Luster filesystem? In other
words, will the MDS always need 400M to work properly for a
filesystem
of size 1T or just 1G? By switching to a different underline
filesystem (i.e., from ext3 to ext2), can this number be lowered?
In fact you do NOT need the full 400MB of journal space, and lconf
will not create a journal that large if you have a smaller
filesystem.
With 1.6beta, I guess the journal is created by mkfs.lustre
--mdt. How
does it know the size of the file system?
mkfs.lustre uses the BLKGETSIZE64 ioctl for the disk size.
That's only the size of the disk for running mdt, right? It's not the
file system size since maybe it's unknown at the time that mkfs.lustre
--mdt is issued (OSTs could be added in the future).
That's correct - mkfs only affect the local disk, and the journal is
specific to the local disk as well. The other OSTs have their own journals.
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