Is there a way to see how many open files there are currently? (NFS4)
Also is there a limit to how many open files a Filer can handle via NFS? And is there any tunables?
This is because we have a customer running open stack on a FAS9k claiming they have over 200k open files from one client...
#NFS Open files ?
limpid shadow
random fjord
files are not really "open" in NFS, not even in NFS4. You might be able to see file locks, or even delegations (if enabled) but in general, NFS does not have a concept of "open files" like SMB for example.
This is probabyl more of a Linux problem, as the Linux kernel has to keep track of every single open file and that uses memory (and CPU) resources. That's why Linux usually limits the number of open files (per process via ulimit and globally via a flag in /sys )
limpid shadow
We tested up against a HDS HUS controller where it stopped working because there was a limit of about 60k open files on the HUS controller.. apparently the NetApp just keeps going to above 200k "open" files..
random fjord
that's strange, as usually the server doesn't have to keep any state (the file handle is a "fixed" number, basically "volume ID + inode number" so it shouldn't change, but then again I have no clue how HDS HUS works so yeah, they might have limits)
limpid shadow
Yeah I am no HDS expert at all... I just happen to know a HDS guy from way back and he was asking me about this, and apparently a customer is getting rid of a NetApp box in favor of HDS... I guess they didn't think it through.. it's usually missing space when HDS wins or "buys" a NetApp customer, they underestimate dedupe etc... As far as I could understand this is an open stack env. with Kubernetes and lots of pods with lots of files... most of them apparently have to be open 😂 The HDS techs are working on a fix I guess...
limpid shadow
Apparently its the number of "stateful connections" on NFSv4 they would like to see on their NetApp... HDS HUS apparently has a hard limit of 64k... which is hardcoded in their FPGA...