Here's a paradox that we only realized recently: in some situations,using RAID-5 can be less reliable overall than using no RAID at all.

This comes about because while RAID-5 preserves your data over asingle-drive failure, it loses all your data if there is ever a doubledrive failure.

Our specific case is a disk-based incremental backup system. Right now aday's backups take up about a third of a disk, and we have it set up soeach day

This is not counting features that Sun has already said they are goingto put in someday, like the ability to remove vdevs from a ZFS pool.The motivation for many of these wishes is good long term storagemanagement , something that ZFS iscurrently weak at.

• the ability to migrate a filesystem from storage pool to storagepool (on the same system) without user-visible downtime or lockups.In theory this ought to be doable, since ZFS is abstracting everythinganyways.

• the ability to control and change what vdevs

Some IP addresses (probably not friendly ones) have recently taken tomaking POST submissions to various 'write comments' URLs here witha Content-Type of 'application/x-www-form-urlencoded; charset=UTF-8'.These get rejected by DWiki , because I was quite paranoid when I wrotethe POST handling code and so DWiki is quite conservative on what itwill accept.

While I was pretty certain that I wasn't losing anything by rejectingthese requests, I did get curious to

The simplistic reason is that only Atom feeds have a distinction betweenthe date an entry was published and the date it was most recentlyupdated. But as far as I know, even fairly deeply Atom aware syndicationfeed readers don't try to do anything much with the field; insteadthey look for changes in the entry's text.

One reason to not use it for much is that the Atom specification is fuzzy about when it getsupdated. The specification says that it is only the time of thelast significant