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

Billich Heinrich Rainer (ID SD) heinrich.billich at id.ethz.ch
Tue Sep 24 09:52:34 BST 2019

Hello Frederik,

Just some addition, maybe its of interest to someone:  The number of max open files for Ganesha is based on maxFilesToCache. Its. 80%of maxFilesToCache up to an upper and lower limits of 2000/1M. The active setting is visible in /etc/sysconfig/ganesha.



On 19.09.19, 16:37, "gpfsug-discuss-bounces at spectrumscale.org on behalf of Frederik Ferner" <gpfsug-discuss-bounces at spectrumscale.org on behalf of frederik.ferner at diamond.ac.uk> wrote:

    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,
    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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