Check Raid Status for Dell Raids on Linux

Linux support from dell is still very poor. They still support only RedHat$ and SuSE$. But there are ways to check the Raid status of Dell server on debian. http://hwraid.le-vert.net/ is doing a good job in collecting information and building Debian style packages. Example:  A Dell server “PowerEdge T130” with “LSI Logic / Symbios Logic MegaRAID SAS-3 …

Continue reading ‘Check Raid Status for Dell Raids on Linux’ »

PaloAlto Packet Loss of 1% and More

Problem: PaloAlto firewall is dropping packets in small bursts of some seconds, and sometimes it drops TCP connections. It only happens on HA clusters on interfaces in active/passive (fail over) mode. Solution: disable the following check box in the Ethernet interface Advanced – LLDP settings: “Enable in HA Passive State” Discussion: Palo Alto uses only one MAC address …

Continue reading ‘PaloAlto Packet Loss of 1% and More’ »

ARP is not working on Cisco ASR 1001 X

Problem: Cisco ASR router is loosing connectivity to its directly attached Ethernet neighbors. In this situation interface status is still up, packets are going in and out on both ends, even IPv6 was still working. The actual problem was that the Cisco ASR was ignoring all ARP responses from its neighbors and the ARP table to this …

Continue reading ‘ARP is not working on Cisco ASR 1001 X’ »

Cups PDF Filter Crashes

Problem: for some PDF files cups does not print the page, the web gui just tells “filter failed” and in the cups logfile you find [Job 528] PID 19521 (gs) crashed on signal 11! Discussion: cups on debian uses ghostscript as pdf renderer. The pdf renderer of ghostsciprt crashes on many files. You can test by simply running …

Continue reading ‘Cups PDF Filter Crashes’ »

Rare Connection Resets after Linux Upgrade

Problem: after upgrading from Debian 6 to Debian 8 some of the machines lose their ethernet network connection under heavy load for some seconds rarely. You find lines like these in syslog: [2333099.217735] NETDEV WATCHDOG: eth1 (tg3): transmit queue 0 timed out [2333099.217966] tg3 0000:03:04.1 eth1: transmit timed out, resetting [2333099.384391] tg3 0000:03:04.1 eth1: 0: Host …

Continue reading ‘Rare Connection Resets after Linux Upgrade’ »

Compiling Sendmail on Debian7

Problem: after compiling sendmail on Debian7 with “./Build” sendmail does not recognize hash .db files. You see the following error message: readcf: map access: class hash not available Discussion: ./Build should detect the berkley DB automatically. When devtools/bin/configure.sh finds libdb.so it adds -DNEWDB as compile option. On Debian7 the libdb.so file moved to /usr/lib/x86_64-linux-gnu/ and configure.sh fails to …

Continue reading ‘Compiling Sendmail on Debian7’ »

Google Maps Marker on Mobile

Problem: A responsive webapp shows a google map with markers that are clickable. On desktop everything works as expected, but on mobile the markers are not clickable. Discussion: After debugging with chrome remote inspector, I found that a div->frame with opacity:0 was lying above (explicit z-index:2) the clickable markers. I don’t know what this frame is for, …

Continue reading ‘Google Maps Marker on Mobile’ »

F5 Drops WebSockets

Problem: F5 LTM is used als load balancer for multiple web servers. When the client opens a websocket connection to the web server, the connection is closed. Discussion: F5 LTM version before 11.6.0 has a bug in the request_log module (profile). The “request_log” module crashes and drops the connection. The bug is a known issue: https://support.f5.com/kb/en-us/solutions/public/16000/600/sol16690.html Solution: If you …

Continue reading ‘F5 Drops WebSockets’ »