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Apr
9
comment How can I keep important VMs in memory without disabling swap?
libvirt.org/formatdomain.html#elementsMemoryTuning (which is needed for this to function) reads like "You can fly without help when you jump from a cliff. The only tricky part is the impact some seconds later, which yet is an unsolved problem."
Apr
9
comment How can I keep important VMs in memory without disabling swap?
Link only answers are bad. Your link broke, so I edited them to the new location. However it is likely they will break again in future.
Mar
16
comment How to create dummy user?
man useradd 2>&1 | egrep -i 'dummy|rights' | wc -l gives 0, so this is a good question!
Nov
13
comment Switch on PAM debugging to Syslog
Other flavours of Unix or anything which dares to use PAM is very welcome, too ;)
Aug
24
comment Why isn't the arc_max setting honoured on ZFS on Linux?
The ZFS arc does not shrink immediately. However (ZFSonLinux) it is reclaimed while applications allocate that memory - as usual. If you need something to hog on memory, perhaps have a look at github.com/hilbix/killmem (only 8K after make static; strip -s killmem)
Jul
18
comment How do I kill processes older than “t”?
etimes works only for newer ps
Jun
14
comment How to debug sporadic outbound connection timeouts?
@Chris Are you DS-Lite or behind NAT? This could be the culprit, because of a full NAT/Translation table (Quota!) on the router or on ISP-level. Then it is not local but just the number of open connections. Others perhaps have less connections and hence are below their connection limit on the routers involved.
Jun
2
comment why is kswapd using high CPU on an idle system?
@Zaz This Q/A is from 2011/2013, but kernel 4.0 is from 2015. So apparently you hit something else. I recommend you to open a new question like "why is kswapd on kernel 4.0 using high CPU on idle system"
Mar
8
comment Easy way to get IP address from hostname using a Unix shell
Nice, and works for IPv6, too.
Mar
8
comment Easy way to get IP address from hostname using a Unix shell
@Ether sed -e '/some people consider Perl a better form/s/better/worse/' SCNR
Jan
23
comment why is kswapd using high CPU on an idle system?
All I have is from the link which is in my post: 2.6.18-194.el5 (RHEL) is affected, 2.6.18-194.32.1.el5 and above is fixed. No idea for other kernel series, sorry.
Nov
5
comment reverse ssh tunnel listens on wrong interface
Also try GatewayPorts clientspecified to make ssh obey your orders. See serverfault.com/questions/379344/…
Jul
12
comment Switch on PAM debugging to Syslog
Please note that all lines like pam_* actually are PAM realated. The other lines are output by the tools anyway, regardless if they use PAM or not. This means: If PAM denies, for any reason, it is really hard to find the real cause, if it is in PAM. The non-PAM lines are not helpful (as the problem sits in PAM) and the PAM lines are often not helpful, too, as they are often too silent. With the presence of many PAM modules you really have a hard time guessing which module might be the culprit, let alone to find out how to enable debugging, as this is different for each single one.
Jul
12
comment Switch on PAM debugging to Syslog
/var/log/auth.log is syslog. The problem is not logging but debugging. If for example the PAM stack fails early, you will not see anything, because the modules which output to syslog are not invoked at all. Or something fails and something not, but both log exactly the same lines. It is correct that, I guess, 95% of all cases can be solved by looking into the usual logs, but 5% cannot, as there simply is no trace of what really happens behind the scenes.
Feb
22
comment Command to prepend string to each line?
awk -v T="[TEST %Y%m%d-%H%M%S] " '{ print strftime(T) $0 }' to output a timestamp
Feb
21
comment Command to prepend string to each line?
sed X cmd does read cmd and does not execute it. Either cmd | sed 's/^/[ERROR] /' or sed 's/^/[ERROR] /' <(cmd) or cmd > >(sed 's/^/[ERROR] /'). But beware the latter. Even that this allows you to access the return value of cmd the sed runs in background, so it is likely you see the output after cmd finished. Good for logging into a file, though. And note that awk probably is faster than sed.
Feb
21
comment Command to prepend string to each line?
T="[ERROR] " awk '{ print ENVIRON["T"] $0 }' or T="[ERROR]" awk '{ print ENVIRON["T"] " " $0 }'
Feb
21
comment Command to prepend string to each line?
awk -vT="[ERROR] " '{ print T $0 }' or awk -vT="[ERROR]" '{ print T " " $0 }'
Feb
20
comment Switch on PAM debugging to Syslog
Thanks. Good hint. I'll try if I ever have problems again. So hopefully never .. ;)
Jan
3
comment why is kswapd using high CPU on an idle system?
Please note that the kswap hanging at 100% was confirmed being a Linux bug. It was fixed in mid/end 2012 kernels.