Re: can postgres run well on NFS mounted partitions?

On Thu, Nov 12, 2015 at 11:49 AM, Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com> wrote:
> On Thu, Nov 12, 2015 at 11:19 AM, anj patnaik <patna73(at)gmail(dot)com> wrote:
>> The Linux VM where postgres is running over NFS is in a different location
>> than where I am. Both the NFS mounted storage and VM are on the same network
>> connected via 1GB ethernet switch.
>>
>> The physical server for the Linux VM has UPS.
>>
>> Is there any specific test I can run to do power failure?
>>
>> Can I reboot my VM to test this or that wouldn't be good enough?
>>
>> Also, why does a checkpoint need to run? I used the graphical installer to
>> install postgres so I assume it would start automatically when the server
>> starts.
>>
>> I was also thinking of blackhole testing. If I do a blackhole to the NFS
>> server would I be able to test this accurately?
>>
>> Folks in the other teams believe NFS should work fine for us so I need to
>> check it out.
>>
>> Your ideas are highly appreciated!
>
> The point of the checkpoint is to make sure as much as possible is
> being written to the data directory when you "pull the plug". But
> without being able to pull the power plugs on the NAS or db server you
> can't really test for reliability in case of power loss. So you can't
> know that it'll survive one. Just disconnecting its network connection
> etc means it can still write out cached data if it isn't properly
> syncing it.

Also note that a UPS doesn't preclude the machine losing its power
supplies etc, or the ever popular faulty power switch / reset button
etc. Which I have experienced on production machines. UPS does not
mean never having a power failure.