On 12/29/2008 8:20 PM, Tim wrote: > > > On Mon, Dec 29, 2008 at 6:09 PM, Torrey McMahon <tmcmah...@yahoo.com > <mailto:tmcmah...@yahoo.com>> wrote: > > > There are some mainframe filesystems that do such things. I think > there > was also an STK array - Iceberg[?] - that had similar functionality. > However, why would you use ZFS on top of HDP? If the filesystem > lets you > grow dynamically, and the OS let's you add storage dynamically or grow > the LUNs when the array does....what does HDP get you? > > Serious question as I get asked it all the time and I can't come > up with > a good answer outside of procedural things such as, "We don't like to > bother the storage guys" or, "We thin provision everything no > matter the > app/fs/os" or <choose your own adventure>. > > > Assign your database admin who swears he needs 2TB day one a 2TB lun. > And 6 months from now when he's really only using 200GB, you aren't > wasting 1.8TB of disk on him.
I run into the same thing but once I say, "I can add more space without downtime" they tend to smarten up. Also, ZFS will not reuse blocks in a, for lack of better words, economical fashion. If you throw them a 2TB LUN ZFS will allocate blocks all over the LUN when they're only using a small fraction. Unless you have, as the original poster mentioned, a "empty block reclaim" you'll have problems. UFS can show the same results btw. _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
