Sunday, December 26, 2010

"Cheating" on an Exchange 2003 Hardware Upgrade

[Project completed in June 2008. Figured this was in my drafts, I should post it.]

Hello Everyone,

I "cheated" on an Exchange 2003 hardware upgrade I did last weekend (Fri-Sat), or that's at least how I feel since this was hands down the fastest and easiest upgrade I've ever done (and it was about 80GB of db's on an older server with direct attached storage). At the end of the weekend, I started to think maybe I should carry around one of these "things" for my clients for upgrades. I'll share what this "thing" was later in the posting. I don't want folks to think I'm pushing products. My role in the project was to insure the replacement of the Exchange Server hardware went smoothly. The client was in production 24/7 and literally the office was staffed 6 days a week. So, I was concerned originally how to insure minimal downtime.

Background on existing hardware & performance
We were upgrading from an Exchange 2003 Server that was installed with 3 hard drives in a RAID 5 hard drive configuration (direct attached storage) for the OS, transaction logs, and Exchange databases. Company had about 60 users and 30 BlackBerrys or so. 1 BES user adds a load similar to 2 Outlook users. So, total company usage was about 120 users. Performance was an issue, so some users were configured for cached mode to "improve" performance. Cached mode should not be required for LANs, unless Outlook end users are receiving "retrieving data from network". Recommended another DAS server that used RAID 1 for the OS, RAID 1 for transaction logs, and RAID 10 for the Exchange databases.

The Migration
So, I checked the OS install (another admin handled that), Exchange install (using the /disasterrecovery switch for setup and service pack 2), Exchange config, and insuring the email & public folder migration completed successful. Only catch was during this server replacement, there was to be no downtime and no use of Exchange clustered services. Hmmm, that's a challenge. Or so one would think.

The Cheat
The client I was working for happened to have a 3rd party product (keeping read to find out) for Exchange that in essence allowed the "cheating". And I mean this in a very good way. It saved me a LOT of time. Meaning, we told the 3rd party product to take over all the existing Exchange services (MAPI, SMTP, OWA, IMAP, etc) and data for the Outlook, OWA, ActiveSync, & BlackBerry was available to all users. All their data was still available. This took a few minutes (3 or 4 minutes) on the switch-over. Now everyone was operating off the appliance and end users didn't know this besides restarting Outlook and re-authenticating to OWA (ActiveSync & BES users had a slight delay. BES users could be out of service for up to 15 minutes, but that's a limitation of BES). Once the appliance took over, we copied over the Exchange databases (.edb/.stm's) using robocopy to the new Exchange 2003 Server. We considered upgrading to 2007, but the appliance and all the associated Exchange applications would have had to been upgraded, and it wasn't cost effective (TCO reminder). So, after we started robocopy-ing, we went home.

Day 2 of the Migration & Failback
I'm not going to go into the details, but migrating took a few hours including getting the SSL certs for OWA and handling all that. Once the new hardware was setup with Exchange, it was time to bring back all the new email. As I previously said, the reason to copy over the databases to the new server, was the appliance then doesn't need to copy over all data, and just new email/data. Once we copied over the databases and transaction logs, we were able to get the Exchange Server fully operational and enable the failback from the appliance. We then failed back from the appliance to the new Exchange Server. This took a lot longer to check that all data was copied from the appliance to the new Exchange Server. This took 10 hours or so and then everyone had to relaunch Outlook and re-authenticate against the new server.

Appliance Details
The "cheat" was an Exchange high availability appliance from Teneros. For the record, this company has been bankrupt and while still in operation as of 7/10, I do NOT recommend purchasing this product. Even though this appliance runs 2 operating systems, Linux and Windows, the entire configuration is on 2 web pages. Meaning, the Teneros support team is really what runs this product, not the Exchange admin. As per the web interface, to say the amount of information and configuration is sparse, is putting it lightly. Overall the product worked well and we ran into 2 glitches due to permissions and resetting process of the AD name due to poor documentation. And the migration process took longer than expected since the status of synchronization is not very accurate. Not a big deal, since end users are working during the failover and failback. Overall solution is very impressive, but I have some doubts since I'm not a big fan of trusting secret functionality of a black box type solution. I like to know how applications work and I do have concerns over Exchange updates or patches breaking the Teneros functionality. If you are curious, pricing is around $10k, give or take a few thousands. If you wanted to see the demo, Teneros did present at the NY Exchange User Group meeting back in November of December of 2007 or check out their website.

-Ben

No comments: