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107 Posts
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1586
June 7th, 2017 01:00
Issues using screen command with OneFS 7.2
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
252 Posts
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June 12th, 2017 10:00
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
450 Posts
1
June 7th, 2017 04:00
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
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107 Posts
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June 7th, 2017 05:00
Hi Chris,
possible running sessions were the first thing I checked but there are no running sessions:
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
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1.2K Posts
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June 7th, 2017 05:00
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