* Posts by Mike 42

3 posts • joined 14 Dec 2009

Lawyers scared of computers

Mike 42

his reasoning makes sense to me

it's easy to misplace a small USB disk, or CD. Give them a good few pounds of paper to carry around and anyone who leaves it on a train is bound to notice they've misplaced something.

also copying and disseminating the paper copy would be much harder and take more time.

Sysadmins shouldn't let users wander around with potentially sensitive data on CD / USB, without hadcuffing the physical media to them, or at least attaching it to a couple of breeze blocks for "security purposes" (and for the lulz).

Should reduce the amount of people wanting to take data out of the safe and secure environment of the office unless it's absolutely nessecary (which it rarely is).

Exchange 2010 dumps single instance storage

Mike 42

re: DAS

the higher GB/Disk of SATA means the physical footprint (Disk count) of a lot of installations will go down. There should be longer MTBF failures on 7.2k drives v 10k's or 15k's so you end up with better reliability at the physical lvel.

replication is all automatically handled within exchange at the HT's by replaying messages and a failure of a DB (Bringing it up on another node) should result in minimum impact to end users, even if it's in a different DC and the sync is delayed.

if we're talking different dc's the I believe the MS reccomendation is at leat 2 copies per DC so any re-seed required should be local and fast (generally). if it is goin to take a while who cares? theres another couple of working copies in anoter DC that users are onnected to.

any problems with the database and it gets flagged up in EMC so no worries there unless you never go in EMC in which case you probably shouldn't be hosting exchange inhoue. Again you are right with the more data over the wire on re-seed cross DC but net speeds have been growing along with disk sizes, even if you need to upgrade the link.

MS have / will have millions of mailboxes they're hosting themselves going onto E2010, (BPOS / Hotmail / Dedicated) and you can bet your life they've plugged numbers into various calculations on multi copy DAS vs less copies SAN, with the SATA solutions coming out a clear winner.

Mike 42

it's a different architecture...

As far as I'm aware SIS was gone in 2007 apart from for attachments anyway. There's no such thing as exchange 2005 as other posters have commented.

SCC (Single copy clusters) have gone in 2010 replaced with DAG's (Database availability group) which is the evolution of 2007 CCR (Cluster continuous replication). This means realistically you are going to go for 3 copies of a database.

Now you could put those copies on expensive SAN, but the since the IOPS requirements of exchange 2010 is much less you can use SATA disks in DAS. HUGE cost savings here despite needing 3 copies of a database. Now for the SATA disks your looking at 1 or 2 TB of storage available per disk, each disk has a set amount of IOPS available and each user has an IOPS requirement based on their mail profile (sent / recieved / size). Mail just sitting in their mailbox doesn't really put additional load on the server.

So you end up with a user count per disk. let's say that's somewhere in the 100-200 user region, and you plan 1 DB per disk. The DB can then grow to 1TB or so, (not the 100GB reccomendation in 2003) and the extra space users are getting (25GB mailbox anyone?) is basically for free as there's no IOPS requirement for data just sitting there.

The 1TB example above assumes no RAID, but with 3 copies of a DB you effectively have RAID database managed at the exchange server level not the disk level. Much more flexible :)

The requirements for 2010, disk wise are therefore SIGNIFICANTLY less than for 2007 or 2003, to the extent it's got storage vendors shaking in their boots because they're not going to be selling as much high end SAN with big arrays and expensive, fast disks.


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