[Lustre-discuss] Ldiskfs formatting

[Lambert, Cedric]

OK, this mounting options does perfectly the trick for my performance tests. Thanks for your help. 
However, I do not understand why I fall into this problem, and maybe some of you could help me :
I think there is something I did not understand in the mkfs options since my MDT behaves perfectly and its formatting takes a long time. 
It is not the case for my OSTs.
Here are the mkfs_cmd used for my Lustre targets :
Mkfs_cmd for my MDT : mke2fs -j -b 4096 -L scratch:MDT0000  -J size=400 -I 512 -i 2048 -q -O dirdata,uninit_bg,^extents,dir_nlink,quota,huge_file,flex_bg -E lazy_journal_init -F /dev/sdb2 97177856
Mkfs_cmd for my OSTs : mke2fs -j -b 4096 -L scratch:OST0000  -J size=400 -I 256 -i 524288 -q -O extents,uninit_bg,dir_nlink,quota,huge_file,flex_bg -G 256 -E stride=64,lazy_itable_init=0,lazy_journal_init=0,resize=4290772992 -F /dev/sdc 2441822902

When I format my OSTs with lazy_itable_init=0,lazy_journal_init=0 , it takes approximatively 12 seconds for the formatting. Without these options it is instantaneous. Thus, there is a difference in the behavior of the command, but 12 seconds is not a lot for formatting 10 TB ! 

Do you have any idea what's wrong in my OST formatting ?
Thank you
Cédric


-----Original Message-----
From: Dilger, Andreas [mailto:andreas.dilger at intel.com] 
Sent: lundi 14 octobre 2013 19:13
To: Lambert, Cedric
Cc: lustre-discuss at lists.lustre.org
Subject: Re: [Lustre-discuss] Ldiskfs formatting

You can try mounting the OST with "-o noinit_itable". This doesn't fix the formatting (not sure why that isn't being recognized), but it prevents the kernel thread from zeroing the inode table.

This could cause problems for e2fsck in the distant future if certain types of corruption are hit, but does not affect testing in any way

Cheers, Andreas

On 2013-10-14, at 7:35, "Lambert, Cedric" <cedric.lambert at hp.com<mailto:cedric.lambert at hp.com>> wrote:

Hello,

Sorry for this trivial question, but I did not find the solution myself :
Everyone in the ldiskfs/ext4 community is happy since the OST formatting is quicker with the uninit_bg and lazy_itable_init features. And I appreciate a lot this feature too !
However, today for a particular test,  When I format my OSTs, I would like this task to be completely finished in order to be sure to have the maximum OSTs bandwidth when I run my benchmarks.

So, I tried the following :
--mkfsoptions="-E lazy_itable_init=0,lazy_journal_init=0"   but no success : formatting is still really quick and as soon as I mount my OST, iostats show me the formatting activity on it.

Is it still possible to format like in the old ext3 age ?

Thanks for your help
Cédric
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