Issues using screen command with OneFS 7.2

Question

Hi community, normally I am using the screen command during important cluster actions as e.g. firmware updates, OneFS upgrades or patching to log and resume interrupted ssh sessions. But I have some clusters with non working screen command. The last tested one is running OneFS 7.2.1.4. The error message is No more PTYs Sorry could not find a PTY screen is terminating The actual TTYs/PTYs at that cluster are as following: CLUSTER-XXX# ls -l /dev/ | grep 'pty\|tty' crw-rw-rw-    1 root  wheel       0,  19 Jun  7 02:18 ctty crw-rw-rw-    1 root  wheel       0, 171 Jun  7 10:38 ptyp0 crw-------    1 root  wheel       1,  79 Jun  7 02:18 ttyU0 crw-------    1 root  wheel       1,  80 Jun  7 02:18 ttyU0.init crw-------    1 root  wheel       1,  81 Jun  7 02:18 ttyU0.lock crw-------    1 root  wheel       0,  40 Jun  7 02:20 ttyd0 crw-------    1 root  wheel       0,  41 Jun  7 02:18 ttyd0.init crw-------    1 root  wheel       0,  42 Jun  7 02:18 ttyd0.lock crw-------    1 root  wheel       0,  46 Jun  7 02:18 ttyd1 crw-------    1 root  wheel       0,  47 Jun  7 02:18 ttyd1.init crw-------    1 root  wheel       0,  48 Jun  7 02:18 ttyd1.lock crw--w----    1 root  tty         1,  86 Jun  7 10:38 ttyp0 crw-------    1 root  wheel       0,  52 Jun  7 02:18 ttyv0 crw-------    1 root  wheel       0,  53 Jun  7 02:18 ttyv1 crw-------    1 root  wheel       0,  54 Jun  7 02:18 ttyv2 crw-------    1 root  wheel       0,  55 Jun  7 02:18 ttyv3 crw-------    1 root  wheel       0,  56 Jun  7 02:18 ttyv4 crw-------    1 root  wheel       0,  57 Jun  7 02:18 ttyv5 crw-------    1 root  wheel       0,  58 Jun  7 02:18 ttyv6 crw-------    1 root  wheel       0,  59 Jun  7 02:18 ttyv7 crw-------    1 root  wheel       0,  60 Jun  7 02:18 ttyv8 crw-------    1 root  wheel       0,  61 Jun  7 02:18 ttyv9 crw-------    1 root  wheel       0,  62 Jun  7 02:18 ttyva crw-------    1 root  wheel       0,  63 Jun  7 02:18 ttyvb crw-------    1 root  wheel       0,  64 Jun  7 02:18 ttyvc crw-------    1 root  wheel       0,  65 Jun  7 02:18 ttyvd crw-------    1 root  wheel       0,  66 Jun  7 02:18 ttyve crw-------    1 root  wheel       0,  67 Jun  7 02:18 ttyvf There are some hints and useful commands in different unix forums but I don't want to test a remount or permissions change at a productive cluster that is running fine. Unfortunately the screen command is working fine as expected at all my virtual clusters. In their documentation DellEMC recommends using the screen command with exception of OneFS 7.1.0.6 and 7.1.1.2. At these OneFS versions the command isn't working as they told. Any ideas? Phil

sjones51 · Accepted Answer

Hi Phil,

This is actually a bug in 7.2.1.4. There is a workaround for it. I know there was a fix in 7.1.1.3 for the error in 7.1.1.2, but according the kb article I read on it, there isn't a fix in the later 7.2 branch yet. (There might be one listed in the actual bug but the kb doesn't reflect that yet.) Either way, the workaround is non-impactful so should be fine on your production clusters. It is recommended that an EMC Support Engineer perform the steps. There is a kb article, but the contents are restricted. Open up a service request and ask for help with article 468380: OneFS 7.1.0.6, 7.1.1.2, and 7.2.1.4: An error stating "No more PTYs" or "Sorry, could not find a PTY." appears when attempting to use screen

https://onlinesupport.emc.com/SRCreate

crklosterman · Answer

If you run a screen -l how many sessions are already running if any. If there are any already running, do a screen -r ####, where #### represents the session of number. Then type exit to close it out. You're right BTW this is BSD troubleshooting not Isilon.

philippspohr · Answer

Hi Chris,

possible running sessions were the first thing I checked but there are no running sessions:

CLUSTER-XXX# screen -list

No Sockets found in /tmp/screens/S-root.

And of course a wipe does not work because of no running sessions...

But I cannot believe that it is only a BSD thing. Because screen is working fine at virtual clusters running the same OneFS version and versions above and below too.

Phil

Peter_Sero · Answer

Quick note: that would be 'screen -ls' to list sessions ('-l' stands for 'login'; screen's option naming scheme is somewhat anachronistic.) My real tip: 'screen -wipe' to clean up orphaned screen connections. hth -- Peter

Isilon

Was this post helpful?