On Wed, Apr 1, 2009 at 4:15 PM, Scott Carey <scott@xxxxxxxxxxxxxxxxx> wrote: > > On 4/1/09 9:54 AM, "Scott Marlowe" <scott.marlowe@xxxxxxxxx> wrote: > >> On Wed, Apr 1, 2009 at 10:48 AM, Stef Telford <stef@xxxxxxxxx> wrote: >>> Scott Marlowe wrote: >>>> On Wed, Apr 1, 2009 at 10:15 AM, Stef Telford <stef@xxxxxxxxx> wrote: >>>> >>>>> I do agree that the benefit is probably from write-caching, but I >>>>> think that this is a 'win' as long as you have a UPS or BBU adaptor, >>>>> and really, in a prod environment, not having a UPS is .. well. Crazy ? >>>>> >>>> >>>> You do know that UPSes can fail, right? En masse sometimes even. >>>> >>> Hello Scott, >>> Well, the only time the UPS has failed in my memory, was during the >>> great Eastern Seaboard power outage of 2003. Lots of fond memories >>> running around Toronto with a gas can looking for oil for generator >>> power. This said though, anything could happen, the co-lo could be taken >>> out by a meteor and then sync on or off makes no difference. >> >> Meteor strike is far less likely than a power surge taking out a UPS. >> I saw a whole data center go black when a power conditioner blew out, >> taking out the other three power conditioners, both industrial UPSes >> and the switch for the diesel generator. And I have friends who have >> seen the same type of thing before as well. The data is the most >> expensive part of any server. >> > Yeah, well I¹ve had a RAID card die, which broke its Battery backed cache. > They¹re all unsafe, technically. That's why you use two controllers with mirror sets across them and them RAID-0 across the top. But I know what you mean. Now the mobo and memory are the single point of failure. Next stop, sequent etc. > In fact, not only are battery backed caches unsafe, but hard drives. They > can return bad data. So if you want to be really safe: > > 1: don't use Linux -- you have to use something with full data and metadata > checksums like ZFS or very expensive proprietary file systems. You'd better be running them on sequent or Sysplex mainframe type hardware. > 4: keep a live redundant system with a PITR backup at another site that can > recover in a short period of time. > 3: Run in a datacenter well underground with a plutonium nuclear power > supply. Meteor strikes and Nuclear holocaust, beware! Pleaze, such hyperbole! Everyone know it can run on uranium just as well. I'm sure these guys: http://royal.pingdom.com/2008/11/14/the-worlds-most-super-designed-data-center-fit-for-a-james-bond-villain/ can sort that out for you. -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
