Reputation
Next tag badge:
102/100 score
38/20 answers
Badges
10 112 234
Newest
 Nice Answer
Impact
~5.2m people reached

1d
comment Firefox will not open with Open VSwitch Installed
'Professional environment' in this case excludes learning and development environments, which this smells of. The close reason is valid.
Jul
13
comment Unable to connect to AWS RDS instance
@Smaxter The first step is to verify that the inbound rules on the RDS instance are set to allow you. Once you've done that, start working with your local network access to figure out how to get out.
Jul
2
comment Can I have dots in a hostname?
@DineshKumarP Yes. The DNS RFCs describe the period character as the delimiter between DNS labels. While non-DNS services such as Avahi or SLP may allow it, DNS itself does not.
Mar
24
comment Amazon EC2 - need to change IP address without downtime
@Greg Pretty much. 1) Rename to ELB (CNAME), 2) Wait. 3) Change public IP on target box to elastic-IP. 4) Rename to target-IP (A record). 5) Wait. 6) Decomission the ELB.
Mar
23
comment Rotating incremental backups using xfsdump
@DJon It's a filesystem-specific tool, so may use XFS internals to maintain what it does. I'm not sure.
Feb
2
comment How does one cluster multiple machines to act as one to run multiple virtual machines on this single-seeming machine?
@ThreaT If it's done at the OS-level the answers have to be generalizable and performant for most use-cases. To provide a perfomant, generalizable solution the OS will have to analyse running processes to discover their locality requirements and respond accordingly. Generalist high-latency parallelism solutions by an OS usually perform less well than app-specific solutions. See MongoDB (relies on OS) vs. Postgress (self-optimization) for an example of single-box scaling issues.
Jan
24
comment ClearCase statistics for LOC, per user
Link only answers are discouraged, as link-rot happens. Please include at least a summary of what can be found in a link.
Jan
24
comment EXT4 Single Larger Volume or Many Smaller Volumes
'structured file-serving' is something like Sharepoint or another document management system. Unstructured is a big mass of excel, word, powerpoint, random images, and whatnot.
Jan
15
comment Parallel Processing and Disk IO for performance. More cores or more servers?
@monkeymatrix Good question. In general, scaling single-threaded processes goes mostly-linearly assuming the only contended resource is CPU. These days one-big-box scales more efficiently than lots of little boxes, but you can scale farther with lots of little boxes. Lots of little boxes won't be AWS-cost-efficient though.
Dec
19
comment Meaning of directories on Unix and Unix like systems
@Pacerier It's a filesystem, but may be safely mounted as a RAM-disk. That said, many programs assume a set structure in there, so actually require persistence.
Dec
13
comment SAN with a few SSD drives, or lots of old fashioned HDDs?
@Beepbeep Yep, but be aware of the tradeoffs. Lots of iops will consume controller resources, which means you won't get max sequential throughput from the HDDs. Lots of sequential throughput on the HDDs can crowd out IO from the SSDs increasing latency due to channel contention. If that matters to you, but them on different channels.
Dec
8
comment Limit Number of TCP connections in Linux Server, to avoid attack
@Mani At a guess it was a, this is the wrong way to attack this problem downvote.
Nov
26
comment Apache reverse proxy access control
What does this do, and why does it to it?
Nov
21
comment
This is the type of voice we need on the mod-staff.
Nov
19
comment Practical ulimits
@AaronCopley I didn't post this, but earlier in the strace log it does just that and pulls down root's NOFILE limit, which is a much more standard {rlim_cur=1024, rlim_max=4*1024}). This isn't going to be a quick thing to find! If this app needs over a million handles, we have problems anyway.
Nov
19
comment Practical ulimits
@AaronCopley I've done some testing, and got an audit-log out of it. Looks like a pam session-start is somehow failing.
Nov
19
comment Practical ulimits
@AaronCopley We have a STIG-like hardened environment. Pam/audit problems are entirely possible. Will try hand-edits tomorrow.
Nov
18
comment Practical ulimits
@AaronCopley I had to back out the change so I don't have a live example at the moment, but the fact as it existed in limits.conf was 85% of the number in file-max. I DO know that the only nofile lines in there are set by puppet, and the user-specific one is the only one getting input.
Nov
17
comment
Back when I was UTC-8, going much past midnight gets into Europe-time very easily.
Nov
13
comment Tcpdump advanced filters
@extrem Unfortunately, I don't know. All of my work is between known endpoints, I haven't had to get familiar with the more sophisticated network monitors.