On 5/16/13 8:06 PM, Tomas Vondra wrote:
> Have you considered using a UPS? That would make the SSDs about as
> reliable as SATA/SAS drives - the UPS may fail, but so may a BBU unit on
> the SAS controller.
That's not true at all. Any decent RAID controller will have an option
to stop write-back caching when the battery is bad. Things will slow
badly when that happens, but there is zero data risk from a short-term
BBU failure. The only serious risk with a good BBU setup are that
you'll have a power failure lasting so long that the battery runs down
before the cache can be flushed to disk.
--
Greg Smith 2ndQuadrant US greg@2ndQuadrant.com Baltimore, MD
PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.com