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Jul
27
comment How to track down bad performance on an api-server
Please update your question with specific details about the problem. This is too general to be asked here. What technology are you using? How are you testing? What have you tried to correct the problem?
Jul
16
comment Servers in different DC's - performance impact
Without details about your application's workload, this is impossible to answer. The read/write ratios, possibility to use local caching and other application specific information is required to know if this would be feasible. So will such a setup impact your applications? Hard to tell without a profile of your workload and testing.
Jul
16
comment Is there a way to prevent the Screen progarm from killing all windows?
What do you mean by "using the command-line application I noticed that this command"? What command line application? Do you mean screen? What command are you running. If you are referring to gnu screen logging or detaching could be possible.
Jun
23
comment Two DNS zones: one for internal, the other for DMZ servers, is it possible?
I recommended not having a nameserver in the DMZ at all. Since it is only one domain, let your registrar serve as the nameserver for that domain. That simplifies things tremendously. If you must operate a nameserver for that one domain, put it into the DMZ and set it as a non-recursive server. For your internal, you can have it forward requests to your ISPs DNS or to Google's. I recommend a forwarding system since all DNS requests will be sent to the forwarding servers vs. looking up directly. This permits for tighter firewall restriction.
Jan
22
comment Unusually high nfs_inode_cache
What versions of RHEL are you using? There was a known issue related to this awhile ago. access.redhat.com/solutions/481743
Jan
22
comment Haproxy using 10GB Memory and 100% CPU with 50k connections
You can reduce memory consumption by having fewer connections. What version of HAproxy are you using? Have you looked at brokenhaze.com/blog/2014/03/25/…
Jan
22
comment Email Sending over Distributed System?
On modern hardware, unless you have huge lists, the bottlenecks are often the recipients rate-limiting requests. Proper tuning of the system and completing the bulk mailing requests at problematic IPs can impact things significantly. Also you may want to read the docs as it specially addresses clustering. mailenable.com/support/MEEICG.pdf
Jul
29
comment How to setup Apache 2.2.3 to send “last modified” etc
The term weak is simply semantics. The point is that using Last-Modified headers in the absence of other caching instructions leaves the cache period up to the HTTP client. If a resource has not been modified since the Last-Modified date, the resource should be considered fresh. In contrast, when using an Expires or Cache-Control header the origin can set an explicit freshness period.
Jul
21
comment ssl certificate - identity not verified with godaddy
Please update the ticket with the specific domain as there are many test tools that can quickly spot the issue.
Jul
10
comment debug mysql crash
Please update this ticket with your mysql error log. What version of MySQL are you using? Please include any other specific errors.
Jun
30
comment How many power circuits do I have in a rack?
I should have said 2x30A 110V. I think that's what we used to have. Don't forget room for a switch (if needed) and out of band tools. The last thing you want is a tripped circuit breaker. Also if you do run near peak, be sure to have your PDU enforce staggered power ups. Nearly any system can cause an amp spike on power-up.
Jun
30
comment When to increase AWS RDS MySQL Server instance to larger CPU/RAM?
What is the performance/capacity problem you are trying to resolve?
Jun
30
comment Nginx port redirection on Ubuntu
Please see serverfault.com/help/how-to-ask. Post your current configurations, state your goals and specific error your are receiving. What results do you get now? Unlike some sites, SF is geared to professional conversations about system administration not a how-to or tutorial discussion group.
Jun
30
comment How many power circuits do I have in a rack?
Most colo facilities will permit no more than 2x20A of power in one rack. Contact your specific colo provider for details. City fire ordinances may limit the power as well. For your systems, I would ask the manufacturer what is the expected amp draw and peak load. You will want to provision power such that you have some overhead for switches, out of band management tools etc. Note that most providers want you to stay within 80% of your peak usage so not to trip circuit breakers.
Jun
30
comment Nginx 502 Bad Gateway - 111: Connection refused, port not being listened to
@ADM I think that error only happens if you try to spin up another pool on the same port. This would need to be verified but I don't think that error occurs if you have two pools with the same name but different ports.
Jun
26
comment No route to host centos
Man pages are your friend. ipset.netfilter.org/iptables.man.html see the delete chain rule.
Jun
26
comment No route to host centos
Your iptables -N rule is creating a new chain. Chains are processed and then passed back into the main rules. So in this case your NRPE rule passes that traffic into the NRPE chain, which does not have an accept rule. By default it will drop traffic.
Jun
26
comment No route to host centos
On the client side (the server you are telnetting from) post the results of route -n. You could have a routing table issue. If you stop iptables on the destination server, can you connect? Also note with NRPE you need to configuration authentication but that should not stop you from connecting to the port.
Jun
25
comment Yum does not install specific RPM version with custom repo
You may have a naming issue. You may want to compare package information between two packages using rpm -qp in your repo. I don't see why you would get this behavior without a repo data, package naming or corrupted RPM database.
Jun
25
comment Yum does not install specific RPM version with custom repo
What is the result of yum list --showduplicates package package-database