[gpfsug-discuss] Ganesha daemon has 400'000 open files - is this unusual?

[Frederik Ferner]

Heiner,

we are seeing similar issues with CES/ganesha NFS, in our case it 
exclusively with NFSv3 clients.

What is maxFilesToCache set to on your ganesha node(s)? In our case 
ganesha was running into the limit of open file descriptors because 
maxFilesToCache was set at a low default and for now we've increased it 
to 1M.

It seemed that ganesha was never releasing files even after clients 
unmounted the file system.

We've only recently made the change, so we'll see how much that improved 
the situation.

I thought we had a reproducer but after our recent change, I can now no 
longer successfully reproduce the increase in open files not being released.

Kind regards,
Frederik

On 19/09/2019 15:20, Billich  Heinrich Rainer (ID SD) wrote:
> Hello,
> 
> Is it usual to see 200’000-400’000 open files for a single ganesha 
> process? Or does this indicate that something ist wrong?
> 
> We have some issues with ganesha (on spectrum scale protocol nodes) 
>   reporting NFS3ERR_IO in the log. I noticed that the affected nodes 
> have a large number of open files, 200’000-400’000 open files per daemon 
> (and 500 threads and about 250 client connections). Other nodes have 
> 1’000 – 10’000 open files by ganesha only and don’t show the issue.
> 
> If someone could explain how ganesha decides which files to keep open 
> and which to close that would help, too. As NFSv3 is stateless the 
> client doesn’t open/close a file, it’s the server to decide when to 
> close it? We do have a few NFSv4 clients, too.
> 
> Are there certain access patterns that can trigger such a large number 
> of open file? Maybe traversing and reading a large number of small files?
> 
> Thank you,
> 
> Heiner
> 
> I did count the open files  by counting the entries in /proc/<pid of 
> ganesha>/fd/ . With several 100k entries I failed to do a ‘ls -ls’ to 
> list all the symbolic links, hence I can’t relate the open files to 
> different exports easily.
> 
> I did post this to the ganesha mailing list, too.
> 
> -- 
> 
> =======================
> 
> Heinrich Billich
> 
> ETH Zürich
> 
> Informatikdienste
> 
> Tel.: +41 44 632 72 56
> 
> heinrich.billich at id.ethz.ch
> 
> ========================
> 
> 
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