xen dev blog

Yeah I tried ndbcluster first then mariadb with galera which doesn't work very well, then percona (which is a modified version of mariadb with gelera) which does work. However it uses optimisitic cluster-wide row locking which causes repeated and problematic deadlocks in write-heavy applications such as forums. Xenforo isn't designed with this in mind (it's not designed to run large forums to begin with). In the end I patched xenforo with a master/slave adapter which will send write request off to a dedicated member of the cluster and read requests pass through to the local cluster instance. This is in effect an emulated master-slave setup now. Not ideal but it's what worked in the end.

Digital point uses ndbcluster but you need about 100GB of ram across all your machines to run it, since the entire DB is stored in ram. It also uses obscene amounts of data even when idle so you need your own rack in a DC with gigabit fibre between the servers.

All in all I've found percona to be the nicest cluster even though it has the obvious drawback of opportunistic locking.

As to XtraDB hot backup: I've always just used a straight replication off to the (geographically separate) backup server and then run a cron'd dump which pauses replication, makes a dated and encrypted backup then resume replication it. You can run traditional replication off any cluster node, so I'll just pick one of the read nodes and use it as a master to the backup slave.

In my mind this is preferable to hotbackups because it doesn't impact the performance of any active member of the cluster. It's a completely passive realtime backup system.

 

I think I just have to finish porting the banner system then we'll open it for testing and bug reports by the whole CDT and donors.

 

Looking into porting existing 2fa to xen 2fa

 

Spent the morning improving xen 2fa security. I needed to port our existing 2fa over to finish the banner system because bidding requires 2fa codes. Hopefully I will have this finished by the end of today

We will incorporate an even better 2fa system to be optionally enabled (similar to duo or authy) after launch.

 

I've now written and tested a php 5 extension to protect xen's 2fa seeds

 

still work to do on finishing 2fa and banner system. working on this today.

currently incorporating my php security extension into a xenforo addon to properly protect 2fa seeds

 

turns out it is extremely annoying to debug a php extension lol