David Browning, Jr. On 10/2/08 10:07 AM, "David Browning, Jr."
<DBrown AT lsuhsc DOT edu> wrote:
> Hey Stan -
>
> We don't have 20TB yet, but I just checked, and right now we back up
> almost 4 TB of Exchange data nightly. We choose to do FULL backups
> overnight with a differential during the daytime.
>
> We have 4 active nodes, with 2 passive in a windows cluster environment.
> We use dedicated storage nodes to backup the Exchange data over fiber to
> LTO-3 drives, and can get all 4 TB done in about 6 hours. Doing the
> math, your 20TB would be difficult to get done in 12 hours (it will
> depend on how many nodes, and how it is backed up), but with updated
> hardware you might be able to get it done.
>
> How much disk are you going to buy? When we have looked at a backup to
> disk, then backup to tape option, it has been VERY pricey. When you
> start pricing out 100+ TB of disk storage, it becomes very expensive.
> At 20TB, you could only keep 5 FULL backups of your Exchange data on
> disk. In our case, we would need at 100 TB just for 2-3 weeks of backup
> data on disk.
>
> So, even though we use an older technology (tape), the old ROI tells us
> that spending $500 K to $1 Million for backups to disk might not be
> worth it. Don't forget Legato licenses that you would have to buy, in
> addition to any hardware necessary.
David;
Thanks for the feedback. We are still in the shopping phase for the hardware
(servers and storage) that we'll deploy for our new Exchange server so we
haven't decided what kind of storage we'll get yet. We have an outside
consultant here now who specializes in large Exchange deployments who is
tasked with helping us identify our hardware needs.
Are you doing any archiving of your Exchange email? I am not necessarily
asking about archiving for legal compliance, but archiving based on time and
frequency of access of messages. Our thinking thus far is that in order to
meet our backup window objective, we have to push old email off to cheap
storage and not back it up on a daily basis.
We are assuming that if we lose our new Exchange server in a disaster
situation, we'll be okay if we recover the actual server and the most recent
20% of email and then worry about recovering older messages later.
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