[Lustre-discuss] inode size with mkfs

[Stuart Midgley]

We are running stock Centos5.4 which has 

# rpm -qa | grep grub
grub-0.97-13.5

# grub --version
grub (GNU GRUB 0.97)

which obviously doesn't have support for 256byte inodes.

We don't actually install our oss's from a distro dvd.  We have a bootable USB disk which is just an image of an oss and we rsync it into place (after formatting the partitions).  This method is VERY useful for disaster recovery.  If we loose / or have booting problems, we can boot of the usb disk and get our oss back quickly.



-- 
Dr Stuart Midgley
sdm900 at gmail.com



On 10/03/2010, at 18:55 , Andreas Dilger wrote:

> On 2010-03-09, at 17:20, Stuart Midgley wrote:
>> After installing e2fsprogs-1.41.6.sun1-0redhat it appears the default inode size for ext file systems changes from 128 to 256 (see /etc/mke2fs.conf).  This caused us several days of "head scratching" as we were trying to figure out why grub wouldn't work on our oss's where we had this package installed.
>> 
>> To resolve the issue, we had to build our /boot partition with
>> 
>>  mkfs.ext2 -I 128 ...
>> 
>> which set the inode size back to 128 for this partition and grub was happy again.
> 
> This seems a bit confusing, since I would imagine that /boot is formatted with the default OS version of e2fsprogs, and the Lustre-patched version is installed after initial installation?
> 
>> So... why was it changed as the default for ALL ext file systems?  Surely, an entry could have been put in for lustre with the correct settings?  ie. mkfs.ext3 -T lustre ....
>> 
>> Stopping something as fundamental as grub from working doesn't seem like a good thing for a package to do.
> 
> 
> This is actually a change in the upstream e2fsprogs-1.41, and was not introduced in the -sun1 patched version.  It was done because ext4 is now using the extra inode space for nanosecond timestamps and xattrs, though I grant that both of these features were first developed for Lustre.
> 
> What version of GRUB are you using?  I know that FC12 is installing ext4 by default, so I imagine that they are using 256-byte inodes with GRUB.
> 
> Cheers, Andreas