Somehow, a comparison of block for block of the zcs disks and the bcs disks come out with zcs having a slightly bigger size.

Under normal conditions, this small size difference would not really be seen, but if you try to do a snapmirror between the two, having the bcs disks as the destination, the filer complains that there is not enough space. So far we have had to work our disks with this formula.

If a volume size of BCS disks is 4 = 1 parity 3 data (36 gig disks), then BCS disks would have to be 3 = 1 parity 2 data(72 gig disks.

If a volume size of BCS disks is 9 = 1 parity 8 data (36 gig disks), the BCS disks would have to be 6 = 1 parity 5 data (72 gig disks instead of 5 = 1 parity and 4 data. So hence 4 data 72 gig disks are smaller than 8 36 gig disks.

KEVIN

-----Original Message----- From: Jeffrey Krueger [mailto:jkrueger@qualcomm.com] Sent: 05 September 2001 17:56 To: Noll, Kevin Cc: 'toasters@mathworks.com' Subject: Re: BCS VS ZCS Zone Disks

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?

-- Jeff

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.

Thanks KEVIN

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