On Sun, Jan 24, 2010 at 10:04:15PM -0800, Ben Calvert wrote: > On Jan 24, 2010, at 5:06 PM, nixlists wrote: > > > > I specifically wrote above "When configured as documented." No admin > > will run a mail server with write-back cache enabled on either > > controller or drives > > really? how sure of this are you? > > let's poll the population of misc@ > > how many administrators of email servers* reading this list have turned off > write caching on > > 1. their raid controllers ( if applicable ) > 2. their disks > > * because, let's be fair to the unnamed individual, he's only concerned with > the special case of serving email. > > Ben >
Corporate email system - thousands of users, TB of data. I turn on every freakin' cache I can find (disk, controller, SAN box, FC Switch, Storage Virtualization infrastructure, OS, etc.) to keep performance acceptable. I backup a lot. I have a lot of redundancy. Since each disk these days has millions of lines of code (really) on it, let alone the firmwares and software levels on all the components mentioned above, and given the quality of corporate software generally, to try and circumvent what the manufacturer recommends is only making your configuration likelier to fail. They have what they test, and a whole whack of 'check box' features they have to provide. Use the former and avoid the latter at all costs. And yes, I have had disk firmware fail, disks crash, FC networks go funny, servers self-immolate, etc. Do you think Google runs gmail with cache disabled? .... Ken
