Jail to jail network performance?

[Robert Watson]

On Sun, 25 Sep 2005, Brandon Fosdick wrote:

> Robert Watson wrote:
>> There are several ways you can do it, but they generally fall into two
>> classes of activies:
>>
>> (1) Modifying the name space exclusion assumption for jails, so that the
>>     file system name spaces overlap.  One way to do this is with nullfs.
>>
>> (2) Having a daemon or tool that runs outside of the jail and brokers
>>     communication between the jails.  One example might be a daemon that
>>     inserts a UNIX domain socket into both jails and then provides
>>     references to shared IPC objects between the two "by request".
>>     Another example might be a daemon or tool that responds to a request
>>     and creates a hard link from a socket/fifo endpoint visible in one
>>     jail to a name visible in another jail, perhaps when setting up the
>>     jail.  The former requires more infrastructure, but the latter is less
>>     flexible.
>
> The jail(8) man page says that if the MIB 
> security.jail.sysvipc_allowed=1 processes inside a jail can use IPC to 
> talk to stuff in other jails. How does that affect mysql in a jail? Do I 
> need this enabled to run mysql?

Last I checked, MySQL used solely TCP and UNIX domain sockets for 
communication, and not System V IPC.  I believe PostgreSQL, however, used 
System V IPC.

Robert N M Watson