jkrueger@qualcomm.com (Jeffrey Krueger) writes:
On Tue, Sep 04, 2001 at 09:54:26PM +0100, Noll, Kevin wrote:
Hi All
We have 9 x F760 Netapp Filers, 4 in Cluster Mode and the 9th one is what we have reserved for Snapmirror.
We currently snapmirror volumes from these 8 filers to the backup filer. However, All existing filers have the old FC9 Disk Shelves with 36 gig disks in, and the new F760 Backup Filer has the new DC14 Disk Shelves with 72 gig drives.
What should have been a disk for disk snapmirror configuration, either by having 36 gig to 36 gig or 36 gig x 2 to 72 gig disk, has become more complicated as the new disks have a different Zone. The new zone makes the new 72 gig disks slightly smaller than 2 x old 36 gig disks.
I was wondering if anyone else might have encountered this problem yet, and if there is any workarounds as to disk zoneing, etc etc.
[...]
It was my understanding that the ZCS disks were actually 520 block-per-sector disks rather than 512 blocks-per-sector and that the checksum was stored in the "extra" 8 blocks. This would essentially make it the same size as a 512 block disk with the same number of blocks, right? Maybe those disks are just smaller anyhow?
That's the wrong way around: it's BCS disks that have 520-byte sectors, and ZCS disks (the traditional ones) that have 512-byte sectors.
I think Kevin's problem is that a ZCS "36GB" disc is right-sized to 34500 MB while a "72GB" disk (of either type) is right-sized to 68000 MB. Hence his volumes on the 72GB discs will tend to be just too small to mirror one on 36GB discs (with an even number of data disks) unless he almost-wastes an extra 72GB disc.
One possibility would be to switch the functions of the servers around, making the filer that holds mirrors use 36GB disks and using the 72GB disks in one or more of the primary filers.
Chris Thompson University of Cambridge Computing Service, Email: cet1@ucs.cam.ac.uk New Museums Site, Cambridge CB2 3QG, Phone: +44 1223 334715 United Kingdom.