Re: ERROR: could not read block 4 ...

"=?UTF-8?Q?Leonardo_M._Ram=c3=a9?=" <l.rame@griensu.com> writes:
> Hi, I'm getting this error:
> 2016-09-15 09:35:24 ART [13984-1] ERROR:  could not read block 4 in file
> "base/12210/11965": Error de entrada/salida

That looks like a hardware problem ... might want to budget for a new disk
sometime soon, before failures become more prevalent.

> 1) Is this caused by a bad block?, can fsck fix it?.

yes, and fsck is unlikely to help, though you could try.

> 2) Is there a way to re-generate template0?.

If you've never modified template1, you could drop template0 and re-create
it from template1.  Otherwise, pg_dumpall/initdb/reload would seem to be
called for.  A cautious person might want to do the latter anyway in case
there's more problems than just this one.

            regards, tom lane