Re: Rackspace to RDS using DMS (Postgres 9.2)

From: Joshua D. Drake Sent: Thursday, September 01, 2016 9:29 AM
On 08/31/2016 03:41 PM, Patrick B wrote:

> Hi guys, I posted this question on the ADMIN list but will post here

> as well so more people can comment...

> <https://www.postgresql.org/message-id/CAJNY3it_AfxJhmwMHtpiAbHG47GS5rJ> https://www.postgresql.org/message-id/CAJNY3it_AfxJhmwMHtpiAbHG47GS5rJ

> OAUgfHw%2BGm5OXCbUm7w%40mail.gmail.com

>

> I've got a 2.3TB Database running at Rackspace... We'll be migrating

> it to RDS PostgreSQL 9.5 very soon...

>

> We already have an EC2 Instance at Amazon running PostgreSQL 9.2 as

> streaming replication from Rackspace.

>

> I'll have to upgrade the version of Postgres on that instance before

> start using DMS service.

>

> *Question:*

> Has anybody ever used that service? I'm just trying to find out how

> much time it will take to perform the migration...

It is 2.3TB, it is going to take a long time no matter what service you are running.

No, I have not used DMS. Frankly, with all respect to AWS/RDS the idea of running a 2.3TB instance that will get any level of performance sounds ridiculously expensive.

Sincerely,

JD

I currently have an EC2 instance in AWS – an m4.xlarge (4 cores, 16gb, 3tb SSDs) and it’s pretty cheap, about $620/mo ($210/mo for the compute, $410 for the storage). The performance of this setup rivals in-house Cisco UCS server that we are demoing that costs ~$100k, as long as our batch sizes don’t exceed available memory – that’s where the larger Cisco pulls ahead. The $620/mo is the on-demand price, btw…the reserved price is much lower.

$100k/ $620 = 161 months of operation before cost parity.

Mike S