"Too many open files" error: Win7, Ultra, RAIDiator 4.2.19

[dmw]

I've just added a Readynas Ultra 4 Plus to my LAN. Until now I had been using an NV+. Each night I run a backup of files on the ReadNAS to a USB drive on my PC, using Genie9 (fka Genie-Soft) Backup. This worked fine with the NV+, but on the Ultra, the backup software monopolises the connection, and any attempt to access the NAS at the same time from the same PC (using Windows Explorer) is blocked. If I try to save open files from my PC to the NAS, I get the Windows error "Too Many Open Files". I can still access the NAS from another machine, so the NAS is not overloaded.

Searching the web, I believe this is a problem with Samba, the underlying OS of the NAS, which doesn't know how to throttle open connections to Windows 7. I tried disabling oplocks on the relevant share via FrontView. This had no effect. The backup is still running, so I have not rebooted the NAS, although I assume disabling oplocks does not require a reboot (FrontView doesn't say it does).

Apparently this bug was fixed in Samba 3.5.0 (bug 6837) released 1-Mar-2010. Or was it? What version is ReadyNAS using in RAIDiator 4.2.19?
http://www.samba.org/samba/history/samba-3.5.0.html

By the way I cannot find the drafts folder after clicking "Save" to save a draft of this message. Luckily I have a copy in notepad.

[dmw]

I've now done a reboot of the ReadyNAS Ultra (as mentioned above, I disabled oplocks on all the shares), and the problem is still the same. Occasionally (maybe 1 in 10 attempts) if you keep clicking in windows explorer, you get a directory listing on the share when the number of open files briefly drops below the maximum (which I read somewhere is 1024). But this is of no practical use for opening and saving files. BTW my flavour of Windows 7 is x64 Ultimate. Netgear please fix this!

[dmw]

I've done further testing. A backup is currently running from the ReadyNAS to my PC, with about 60,000 files processed out of about 236,000. The NAS was accessible from the PC which is running the backup software until it got past about 16,000 files, then it became inaccessible. I used Windows Resource Monitor to look at the "Associated Handles" of the process which is running the backup. It appears that there are about 16,384 (2^14) handles for open files. I can see the directory names in the handles, which are nearly all in the first 16k files the backup would encounter.

So it seems that Samba on the ReadyNAS is not closing the files to the satisfaction of Windows 7 x64. The backup continues after that though, so these files have all been processed. If I stop the backup mid-way, then the NAS remains inaccessible until I close the backup program on the PC, killing the process, which releases the open files. Then I can access the NAS again.

Again, what version of Samba is running on x86-based ReadyNAS machines? I suspect that it is using an old version of Samba before the fix was introduced in Samba 3.5.0. Here's the change log again (search it for BUG 6837: "Too many open files" when trying to access large number of files from Windows 7):

http://www.samba.org/samba/history/samba-3.5.0.html

[dmw]

Netgear support tells me:

Upon consulting our Engineering, they have informed me that the SAMBA version used on 4.2.19 for x86 NAS is version 3.5.11.

That may be useful to other forum members. However, I still don't know what is causing the "too many open files" problem. Anyone else have a similar experience?