Interview Stuff

https://docs.google.com/document/d/1hxnrh7nm24IqtFXsSQqwv4Arx4cxlD9t29cfpKQRRx8/edit
https://www.youtube.com/watch?v=55aEVvITNJ0&feature=em-u
https://www.youtube.com/watch?v=tndzLznxq40 designing tinder

Interview stuff: https://jvns.ca/blog/2013/12/30/questions-im-asking-in-interviews/

https://www.quora.com/How-do-I-prepare-for-Google-and-Microsoft-interviews-from-a-no-name-college

See Meep stoof

"How might we want to design email server infra?"
-> high availability server for more recent emails, else on commodity H/W

FB PE Sys Screen:
- explain fork/exec, virtual mem, copy on write, threads, process states
- load average is high, but cpu utilization is low. -> uninterruptible disk I/O must be high.
- find processes doing most disk I/O with iostat. strace it to see hanging instruction: fstat(34)
- lsof file descriptor 34 to find where it is, go there, ls hangs. that's odd, inodes are just metadata.
- then metadata is inaccessible. where is the file? it's in /mnt. is it an nfs mount? yes.
- ok, is this machine provisioned with some tool? yes - chef. ok, check chef configs to find machine of nfs mount.
- it's a raid array. cat /proc/mdstat for issues - a drive is failed. misconfigured! fix it with mdadm.