[lustre-discuss] MDT filling up

[Thomas Roth]

Ah, yes, thanks Andreas.
Those many symlinks are just the right size, 64 or 65. That explains it.

Best regards,
Thomas

On 6/28/21 8:19 AM, Andreas Dilger wrote:
> On Jun 26, 2021, at 12:58, Thomas Roth <t.roth at gsi.de<mailto:t.roth at gsi.de>> wrote:
> 
> 
> we have one of three MDTs filling up its disk space. It is running 2.12.5 on ldiskfs, but no data-on-metadata.
> The inode usage is just 54%, corresponding to 477 M inodes.
> 
> There is a large directory tree with 353 M files. For each or many of these files, there is also a symlink.
> 
> This is about the only oddity of this MDT.
> Could it be that those symlinks eat up all the remaining space somehow?
> 
> It depends on how long the symlinks are.  Anything over 60 chars is allocated in a separate 4KB block, so if you have a large number of symlinks then this could definitely consume a lot of blocks on the MDT.
> 
> Hard links, on the other hand, consume space in directory blocks, but these are typically shared with other names and only consume as much space as the final name component, not the whole pathname.
> 
> Cheers, Andreas
> --
> Andreas Dilger
> Lustre Principal Architect
> Whamcloud
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