[Lustre-discuss] How to change inode capacity

Satoshi Isono satto11 at sage.ocn.ne.jp
Thu Jan 29 18:58:27 PST 2009

Hi Brian,

Thank you for your reply. I inserted my comment into your lines. please refer it.

At 09/01/30(金)04:36, Brian J. Murrell wrote:
>On Thu, 2009-01-29 at 13:32 +0900, Satoshi Isono wrote:
> > Hi all,
> >
> > Do you know how to change the capacity of inode space?
>Sorry, you can't.  Up-front planning is very important in this aspect of
>deploying Lustre.  In the future, adding MDTs will increase inode
>capacity, but currently only a single MDT is supported.

Current Lustre version is NOT able to multiple MDT. Is it right? I 
found the article in Lustre FAQ.

    * What is the maximum number of files in a single file system? In 
a single directory?

So, if we use current Lustre 1.6.x on EXT3, we can only support 
single MDT. Then, according to the limitation of the number of 
inodes, we are able to use inodes up to 4 billion. This means that a 
Lustre consisted on EXT3 can support 4 million files. Is it correct?

>I *think* growing the size of the physical device and then using
>resize2fs to increase an ext3(4?) filesystem will increase inode count.
>I am however, doubtful that resize2fs will work with our ldiskfs
>filesystems.  Perhaps resize2fs from an ext4 supporting version of
>e2fsprogs will support doing that.  I have no idea -- never tried it.

Another question to you, When changing #inodes into maximum number, 
are there any demerit/un-merit points? I want to know the tradeoff 
changing #inodes. In my site, the total OST capacity is 800TB and 
size of MDT is 123207680 (123 million). What do you think about the 
number of inodes which I will change?

>That said, doing this is a completely unsupported operation.  I don't
>know anyone that has even tried it.  If you want to go this route, do a
>lot of testing and make sure you have backups.
>It will probably be easier and cheaper in the long run to just build a
>new MDT that meets your revised requirements.

I understand. Of course, I am going to choose more safety way to change #inodes.

I appreciate your advice.
Satoshi Isono

>Lustre-discuss mailing list
>Lustre-discuss at lists.lustre.org

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