Our volumes are similarly large, mostly around 300 GB with a few closer to 600 GB. Fortunately, with ONTAP 6.x and NDMP, you can now use Direct Access Restore (DAR), so the restore times (for individual files at least) increases dramatically. As far as other issues we have seen with the large volumes, we tend to "waste" drives because we keep at least two as hot spares. Of course, the largest drives we are using are 36 GB; on our filers with 18GB drives, we usually keep 5 drives as spares to allow for failures and/or future growth.
We typically only have two volumes on a given filer, one root (usually two 18 GB drives, one data, one parity) and one vol0 (the rest of the disks, the number of which varies depending on the size of the drives). If you use qtrees to split this vol0 up into four even parts, you can avoid much of the headaches of large volumes; NetApp recommends four concurrent backup streams on a F760 (and I would guess the same would be true of the F8xx series). If you back up, and restore, the four qtrees separately, you should see fairly reasonable times, especially with directly attached tape drive(s) and DAR.
Geoff Hardin Dallas Semiconductor geoff.hardin@dalsemi.com
"Brian L. Brush" wrote:
We have an F760 with two shelves of 72 GB drives. There are two volumes of five drives each. We now face the decision to expand one of the volumes or create a new three-drive volume, leaving one hot spare.
If we create a new volume, we lose yet another large chunk of space for parity. (We also get a small number of spindles, but performance hasn't proven to be a problem in our situation.)
If we expand an existing volume, we get an uncomfortably large volume. The volumes are already 215 GB.
We're leaning toward the latter resolution, because disk usage inexorably increases, and purchasing more hardware is not an option even on the horizon.
How have others dealt with these matters? Do such large volumes entail problems beyond the obviously longer backup and restore times? Are we overlooking any major issues?
--Brian L. Brush Senior Systems Administrator Paradyne Corporation