Samba Share Concurrent Access Issue

[FlyingHacker]

Dell 730xd 6x2 mirrored vdev
TrueNAS Core 13 U1

This is a new build.

I have 22 Windows (8 and 10) client machines all connected via a mapped letter drive. One machine is 10Gig ethernet. The others are 1Gig ethernet, but connect to the server through the same 10 Gig port (all use the same IP). When they all attempt to read the same 965MB file at once some of them somehow fail to read the file. I will try to gather more data on precisely what the error is (the software doesn't report errors directly, but there may be a log I can check next time I do this).

I guess I should add the clients are all READING the file only.

Anyone heard of anything like this?

I don't see much in the server logs other than a TON of these (multiple per second every few minutes):
[2022/07/14 11:25:07.814311, 1] ../../source3/smbd/service.c:357(create_connection_session_info)
create_connection_session_info: guest user (from session setup) not permitted to access this share (MyShare)
[2022/07/14 11:25:07.814377, 1] ../../source3/smbd/service.c:546(make_connection_snum)


I copied the file over to our old Synology NAS (1 Gig only) and everything works fine.

Thanks in advance.

 

[FlyingHacker]

I am doing some more tetsing. Stil having the issue, cannot find anything on the client side that gives an error, but I am seeing these in the samba log:

[2022/07/14 17:04:13.425458, 1] ../../source3/smbd/scavenger.c:680(scavenger_timer)
scavenger_timer: Failed to cleanup share modes and byte range locks for file 2370232465894507985:427485:44905 open 2152580552

 

[FlyingHacker]

After much testing and pulling of hair I finally found a solution...

The problem is the oplocks were causing the issue. In my case it was some ~1GB files that are read by about 20 clients at the same time. They are opened only for reading (though who knows what the actual closed source software does).

I was able to disable oplocks on this filetype on this particular share using this in the Advanced Options-> Auxiliary Parameters.
veto oplock files = /*.typ/*.TYP/*.etc/*.ETC/

...where "typ" and "etc" are the appropriate file extensions.