Recent Slow Website Performance in LAMP Setup When DB Job is Run in Background

Posted on 2014-09-06
Medium Priority
Last Modified: 2016-11-23
We are running a LAMP platform which has the following hardware:

-Two Dell R200's running Red Hat (one separate website on each) serving as web servers
-Cisco Smart switch
-One Dell 2950 w/32 gb RAM, 2Xquad core XEON 2.3 ghtz CPU's and 8 x 600gb SAS 10k RPB drives (two RAID groups 1-  RAID1 for Solaris OS and 2-  5+1 RAID5 w/hot spare

Things seem to be going well  until about a month ago, when the performance of the websites would take huge latency hits whenever we ran a database job in the background. Bear in mind that we have been doing this in production since early November, 2013.

Now, however, whenever we run one of these jobs (e.g., updating tables, backing up database, etc.) the response rate for the server tanks severely.

We've absolutely ruled out the issues being related to the network or the Web servers (after many hours of diagnostics).

We carefully checked out all aspects of the Dell 2950. We've run Dell diagnostics against the entire system (as well as Solaris CPU, memory test commands) and it reports that all of the CPU threads are healthy, the RAM is 100% operational in the disk drives in the raid groups are fine.

We decided that the volumes on the server are exceeding some performance threshold and we think that we're going to drop two gigabit network cards (Intel E1G42ET) into the 2950 and move everything into a Dell 3200 ISCSI San.

We could then re-create the luns across 12 drives (and probably continue to use the 2950's first raid one group for the OS).

My question is: will this alleviate these latency issues that have popped up over the last month?  What might be a better approach?
Question by:bhunger
LVL 11

Accepted Solution

Murfur earned 2000 total points
ID: 40312339
By your troubleshooting you seem to have decided that the problem must lie with the Dell 2950 offering the RAID but I'm not so sure.

My initial guess would be that the problem lies within MySQL

What is the slow MySQL job actually trying to do? Where is your MySQL installation - local or remote? Assumption is local given that you looked to the RAID for the solution but if not actually connecting to "localhost" then you might want to prevent MySQL from making DNS lookups by adding skip-name-resolve to your MySQL conf.

If you are running backups/dumps then you might want to consider taking them off that server as processes go, they are notoriously resource hungry. For example, you could set up MySQL replication and have the jobs run from the slave thereby leaving the sites to access the master with "normal" performance. FYI a master server will handle all inserts & updates but a slave will only accept selects and the backups running from that won't affect performance on the master.

Digging deeper, you need to look at all elements of the transaction as any one of them could be the cause of the bottleneck:
Web site -> web server -> MySQL service -> MySQL server and of course the connections in-between them all.

Activate the slow query log to see if you can spot a particular bottleneck. Look out for table locks or queries with too many joins etc.

That should get you going for a start but let me know how you get on...

Author Closing Comment

ID: 40313089
Thanks for the answer.  We'll follow your recommendations and see where it leads us.

Featured Post

2018 Annual Membership Survey

Here at Experts Exchange, we strive to give members the best experience. Help us improve the site by taking this survey today! (Bonus: Be entered to win a great tech prize for participating!)

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Windows Server 2003 introduced persistent Volume Shadow Copies and made 2003 a must-do upgrade.  Since then, it's been a must-implement feature for all servers doing any kind of file sharing.
This applies to Dell but may also apply to other manufacturers as well. We ran across a few machines that just dropped recently it trust relationship with the server. After doing the basic removing and joining the domain again, it changed to No logo…
This Micro Tutorial will teach you how to reformat your flash drive. Sometimes your flash drive may have issues carrying files so this will completely restore it to manufacturing settings. Make sure to backup all files before reformatting. This w…
In this video, Percona Director of Solution Engineering Jon Tobin discusses the function and features of Percona Server for MongoDB. How Percona can help Percona can help you determine if Percona Server for MongoDB is the right solution for …
Suggested Courses
Course of the Month6 days, 12 hours left to enroll

593 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question