Dear Linux CIFS list, We are experiencing an issue when the number of simultaneous mounts reaches about 70. The users experience that they cannot access their mounted shares, though only periodically. The shares are permanently mounted in the users homedirs by root (using a suid wrapper and script). Example error messages seen from the user: [user@myclient]$ ls hdrive ls: cannot access 'hdrive': Permission denied [user@myclient]$ ls projstat ls: cannot access 'projstat': Resource temporarily unavailable After some retries, they regain access. It can be very sporadic, for instance an "ls <mount>" will fail, but moments later a "cd <mount>" will succeed. Sometimes it is necessary to unmount and mount the shares in order to regain access. In /var/log/messages we find messages such as these, correlating with times when the users report the issue: Nov 2 15:27:31 myclient kernel: cifs_setup_session: 40 callbacks suppressed Nov 2 15:27:31 myclient kernel: CIFS VFS: \\myserver Send error in SessSetup = -13 Nov 2 15:27:31 myclient kernel: Status code returned 0xc000006d STATUS_LOGON_FAILURE The messages repeat several times. The client-specific log (/var/log/samba/log.myclient) on the Samba server does not show any messages that would correlate in time with the issues on the client. We have two identical Linux clients that are not experiencing the issue. The number of mounts on those clients is much lower. In addition, we have a large number of Windows 10 and Windows 2016 clients that do not experience any issue at all with the Samba server. The environment: Client: Red Hat Enterprise Linux release 8.2 (Ootpa) Kernel version: Linux myclient 4.18.0-193.19.1.el8_2.x86_64 #1 SMP Wed Aug 26 15:29:02 EDT 2020 x86_64 x86_64 x86_64 GNU/Linux mount.cifs version: 6.8 Server: HP-UX B.11.31 HPE CIFS Server B.04.05.15.00, based on Samba 4.5.15 Any suggestions on how to proceed? I suppose the next step for us is to enable additional debug, and collect tcpdump captures. _____________________________________________ Sune Stjerneby Senior Operations Specialist (UNIX) 662.01 IT Platform & Technology Services NNIT A/S Østmarken 3A DK-2860 Søborg Denmark +45 3079 9461 (mobile) snsy@xxxxxxxx This e-mail (including any attachments) is intended for the addressee(s) stated above only and may contain confidential information protected by law. You are hereby notified that any unauthorized reading, disclosure, copying or distribution of this e-mail or use of information contained herein is strictly prohibited and may violate rights to proprietary information. If you are not an intended recipient, please return this e-mail to the sender and delete it immediately hereafter. Thank you. _____________________________________________ Sune Stjerneby Senior Operations Specialist (UNIX) 662.01 IT Platform & Technology Services NNIT A/S Østmarken 3A DK-2860 Søborg Denmark +45 3079 9461 (mobile) snsy@xxxxxxxx This e-mail (including any attachments) is intended for the addressee(s) stated above only and may contain confidential information protected by law. You are hereby notified that any unauthorized reading, disclosure, copying or distribution of this e-mail or use of information contained herein is strictly prohibited and may violate rights to proprietary information. If you are not an intended recipient, please return this e-mail to the sender and delete it immediately hereafter. Thank you.
