On Fri, Aug 27, 2010 at 05:05:45PM -0400, David Nolan wrote:
> We're hearing a lot of what we consider to be FUD from the vendors
> about each others products, specifically from the dedup vendors. I'd
> love to get some less biased opinions.
Yes, they're quite good at that. It was one of the most frustrating
parts of our purchasing efforts.
We looked seriously at Sepaton and DataDomain. Initially we had ruled
DataDomain out since they didn't have a big enough system, but they
released the DD880 while we were looking.
We ended up going with DataDomain, particularly since we back up a lot
of Oracle database, and using NFS with RMAN is a good combination.
I still have a lot of respect for Sepaton's products, and would suggest
looking hard at what they do to see if it fits your needs.
We've had pretty good luck with DataDomain, and also have been very
happy with their responsiveness and willingness to involve engineering
about new features and optimizing what we already have.
> I'm also interested in real world experience with WAN replication
> cross country (80ms RTT) and globally (250ms RTT). What were your
> replication windows and how much bandwidth did you require to
> replicate that data.
We replicate from Boston to Dallas, about 40ms. DataDomain's replication
only sends deduped & compressed data, so it's really efficient. I think
we peak at 300-400Mbit/sec. Here's a snapshot of the replication that's
running right now so you can see the pre-comp/post-comp usage:
sysad...@dd880-1# replication show performance all
08/28 10:53:27
rctx://1 rctx://2 rctx://3
Pre-comp Network Pre-comp Network Pre-comp Network
(KB/s) (KB/s) (KB/s) (KB/s) (KB/s) (KB/s)
--------- --------- --------- --------- --------- ---------
167283 170 0 0 0 0
235187 353 0 0 0 0
137559 182 0 0 0 0
239336 333 0 0 0 0
115908 263 0 0 0 0
87375 202 0 0 0 0
254204 244 0 0 0 0
158608 338 0 0 0 0
175434 247 0 0 0 0
219142 221 0 0 0 0
Our Oracle databases have a very high rate of change, so we don't get
especially good dedupe. Here's one of their stats commands that show
dedupe over time. We do cumulative backups sunday night thru thursday
night, and our fulls run friday night to sunday morning.
sysad...@dd880-1# filesys show compression daily-detailed
From: 2010-07-24 12:00 To: 2010-08-28 09:00
Sun Mon Tue Wed Thu Fri Sat Weekly
------- ------ ------ ------ ------ ------ ------- -------
------------------
-25- -26- -27- -28- -29- -30- -31- Date
10027.9 1548.3 2083.6 2280.8 2571.3 2831.0 8667.8 30010.7 Pre-Comp
400.5 340.9 444.5 459.5 516.5 562.0 580.9 3304.8 Post-Comp
6.9x 1.2x 1.3x 1.3x 1.4x 1.4x 3.6x 2.4x Global-Comp Factor
3.6x 3.8x 3.7x 3.7x 3.7x 3.7x 4.1x 3.8x Local-Comp Factor
25.0x 4.5x 4.7x 5.0x 5.0x 5.0x 14.9x 9.1x Total-Comp Factor
96.0 78.0 78.7 79.9 79.9 80.1 93.3 89.0 Reduction %
-1- -2- -3- -4- -5- -6- -7-
11878.4 2524.1 2712.0 2962.9 3650.6 3338.0 9386.9 36452.9
662.9 468.4 538.7 559.9 636.9 568.4 606.9 4042.2
5.1x 1.5x 1.4x 1.4x 1.5x 1.6x 4.0x 2.5x
3.5x 3.6x 3.6x 3.7x 3.7x 3.7x 3.9x 3.7x
17.9x 5.4x 5.0x 5.3x 5.7x 5.9x 15.5x 9.0x
94.4 81.4 80.1 81.1 82.6 83.0 93.5 88.9
-8- -9- -10- -11- -12- -13- -14-
10177.3 3158.6 3354.5 3665.9 3886.6 4088.8 11441.3 39772.8
283.4 635.8 606.8 657.0 660.4 686.1 1078.2 4607.8
9.7x 1.3x 1.5x 1.5x 1.6x 1.6x 2.7x 2.3x
3.7x 3.7x 3.6x 3.7x 3.7x 3.7x 4.0x 3.8x
35.9x 5.0x 5.5x 5.6x 5.9x 6.0x 10.6x 8.6x
97.2 79.9 81.9 82.1 83.0 83.2 90.6 88.4
-15- -16- -17- -18- -19- -20- -21-
18124.2 1390.1 1913.9 2238.9 2631.0 3047.1 15407.8 44753.0
1143.1 319.9 434.7 467.7 510.7 569.2 1248.4 4693.6
4.1x 1.2x 1.2x 1.3x 1.4x 1.4x 3.1x 2.5x
3.8x 3.8x 3.7x 3.7x 3.7x 3.7x 3.9x 3.8x
15.9x 4.3x 4.4x 4.8x 5.2x 5.4x 12.3x 9.5x
93.7 77.0 77.3 79.1 80.6 81.3 91.9 89.5
-22- -23- -24- -25- -26- -27- -28-
13911.3 1417.4 2070.1 2439.3 2735.1 3458.3 12029.0 38060.6
713.1 308.8 457.4 505.7 555.6 596.1 960.7 4097.5
5.4x 1.2x 1.2x 1.3x 1.3x 1.5x 3.2x 2.5x
3.6x 3.7x 3.7x 3.7x 3.7x 3.9x 3.9x 3.8x
19.5x 4.6x 4.5x 4.8x 4.9x 5.8x 12.5x 9.3x
94.9 78.2 77.9 79.3 79.7 82.8 92.0 89.2
------- ------ ------ ------ ------ ------ ------- -------
Pre-Comp Post-Comp Global-Comp Local-Comp Total-Comp
(GiB) (GiB) Factor Factor Factor
(Reduction %)
--------------- -------- --------- ----------- ---------- -------------
Currently Used: 318551.7 43533.3 - - 7.3x (86.3)
Written:*
Last 34 days 189050.0 20745.9 2.4x 3.8x 9.1x (89.0)
Last 24 hrs 12093.5 961.0 3.2x 3.9x 12.6x (92.1)
--------------- -------- --------- ----------- ---------- -------------
* Does not include the effects of pre-comp file deletes/truncates
since the last cleaning on 2010/08/23 12:02:17.
Key:
Pre-Comp = Data written before compression
Post-Comp = Storage used after compression
Global-Comp Factor = Pre-Comp / (Size after de-dupe)
Local-Comp Factor = (Size after de-dupe) / Post-Comp
Total-Comp Factor = Pre-Comp / Post-Comp
Reduction % = ((Pre-Comp - Post-Comp) / Pre-Comp) * 100
***
The CLI on the DataDomain is excellent. I never use the web interface.
When we were looking at the Sepaton, they had no CLI.
Let me know if you've got other questions!
-j
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