Search Results

Search found 4 results on 1 pages for 'bramp'.

Page 1/1 | 1

How to configure mod_proxy_balancer to gracefully fail under high load

- by bramp

We have a system which has one Apache instance in front of multiple tomcats. These tomcats then connect to various databases. We balance the load to the tomcat with mod_proxy_balancer. Currently we are receiving 100 requests a second, the load on the Apache server is quite low, but due to database heavy operations on the tomcats, the load there is roughly 25% (of what I estimate they can handle). In a few weeks there is an event happening and we estimate that our requests will jump significant, maybe by a factor of 10. I'm doing everything I can do reduce the load on our tomcats, but I know we are going to run out of capacity, so I would like to fail gracefully. By this I mean, instead of trying to deal with too many connections which all timeout, I would like Apache to somehow monitor average response time, and as soon as the response time to Tomcat is getting above some threshold, I would like a error page displayed. This means that users who are lucky still get a page rendered quickly, and those who are unlucky get a error page quickly. Instead of everyone waiting far too long for their page, and eventually everyone timing out, and the database being swamped with queries which are never used. Hopefully this makes sense, so I was looking for suggestions on how I could achieve this. thanks

Read the article
How to configure mod_proxy_balancer to gracefully fail under high load

- by bramp

We have a system which has one Apache instance in front of multiple tomcats. These tomcats then connect to various databases. We balance the load to the tomcat with mod_proxy_balancer. Currently we are receiving 100 requests a second, the load on the Apache server is quite low, but due to database heavy operations on the tomcats, the load there is roughly 25% (of what I estimate they can handle). In a few weeks there is an event happening and we estimate that our requests will jump significant, maybe by a factor of 10. I'm doing everything I can do reduce the load on our tomcats, but I know we are going to run out of capacity, so I would like to fail gracefully. By this I mean, instead of trying to deal with too many connections which all timeout, I would like Apache to somehow monitor average response time, and as soon as the response time to Tomcat is getting above some threshold, I would like a error page displayed. This means that users who are lucky still get a page rendered quickly, and those who are unlucky get a error page quickly. Instead of everyone waiting far too long for their page, and eventually everyone timing out, and the database being swamped with queries which are never used. Hopefully this makes sense, so I was looking for suggestions on how I could achieve this. thanks

Read the article
Automatically updating routing table on server

- by bramp

I have a LAN with three routers on it, one connected to the Internet, one VPN router connected to a few remote sites, and a final route connected to a private network (using BGP to get prefix advertisements). On the same LAN I have multiple Linux servers which needs access to the networks behind each router. I have achieved this by configuring static routes on the server, pointing the different network prefixes to the correct router. This has worked well, but every time we connect to a new remote VPN, we have to change all the servers to be aware that the network is now accessible via the VPN, and not via the default Internet route. What I want is a way to automatically update the routes on all of the servers, when the route is added to a routers. Now, I could install Quagga or something similar on all the servers to receive router advertisements, but that seems like overkill. So my question is what is the easiest/simpliest way to update the routing tables on the server automatically, and what protocol is best suited for this purpose. thanks

Read the article
RAID controller dropping the wrong drive

- by bramp

I've been having an issue with 3ware 9500S-8 RAID 10, and I have contracted their tech support, but I wanted to hear the serverfault community's recommendations. Firstly, all my data is backuped and secure, so I don't mind blowing my RAID away if I have to. But let me describe the problem I've been seeing. A month ago, disk 6 dropped out of the RAID. It is mirrored with disk 7, so I wasn't that bothered. I went to the data centre and replaced it. When I got back to the office, I noticed that disk 6 will still not in the RAID, and in fact the controller was show the name of the old drive still. A week later I went back and replace the drive again, thinking I might have swapped in a bad drive. Still the same problem. I decided to reboot the machine, to see if that would "force" the controller into seeing the new drive. It did, and a rebuild started to happen (from disk 7). Eventually both drives were showing as good. A week later, the MySQL database has flagged the database is corrupt, and is unable to repair it. I don't know what has gone wrong, but I suspected this 6-7 pair. At this point I noticed that the RAID had constantly been verifying itself, over and over. Regardless of this I began to rebuild the database, which took about 19 hours. It's a big database. Near the end of the repair, the RAID controller told me it had dropped disk 7, and that some data was most likely corrupted. I contacted LSI tech support, and they very promptly started to help me. I mentioned that drive 7 had been dropped. They suspect that drive 7 was always at fault, and drive 6 had always been good. I want to know how often a RAID controller would drop the wrong drive (in this case dropping drive 6 a month ago, instead of 7). I foolishly didn't run smartctl on the drives before I started swapping them out. I just assumed the RAID controller knew what it was talking about. I think my plan of action is to replace drive 7, rebuild the array from scratch, double check smartctl on ALL the disks, and then start restoring my data again. I would appreciate anyone's input on what the correct procedure for swapping drives is, and how often failures like this happen. If anyone would like more information then I'd be happy to provide it. thanks in advance. Oh some more information. I'm running CentOS 5.3, with two RAID arrays, a simple RAID 1 for the OS, and RAID 10 for the database. Both arrays are on different controllers. The RAID 10 is made of 10 identical ST3640323AS drives, until I swapped in a SAMSUNG HD103SJ last month.

Read the article

1