Hey Vishal,
We basically do this at the moment and we have issues with our ability to
stream data to the tape drives in a timely manner, this is mainly to do with
connectivity issues within our environment.
A few questions
1. what sort of network is the DD, Storage node & Tape Library connected to 1Gb
or 10Gb Ethernet, or FC (and what speeD), and how many connections?
2. what sort of tape drives are you cloning to?
3. how many tape drives will you be using for cloning?
4. are you looking at using the new functionality DDBoost over Fibre-Channel?
5. what is your Data Centre structure, single or multiple DC's.
Our environment where we clone to tape is unfortunately restricted to 1Gb
Ethernet, our DD has 10 x 1Gb ports, and we are running 2 storage nodes each
with 4 x 1Gb ports, while I suspect there are issues with NIC teaming, and the
way that it is load balancing across the NICs we are only getting in-between
20-50MB/s streaming to an LTO5 drives (which is really bad) we try and run 4
clone jobs per Storage Node for a total of 8 parallel clone jobs ... and before
you ask, reducing the number of jobs doesn't increase the clone speed. The only
thing saving us at the moment, is that we cross our backups to DD's in opposing
datacentre's, and then clone down to a 3rd DD, so the tape out is basically 3rd
offsite copy, and I'm trying to get management to re-consider the value we are
getting out of tape.
Doing some quick calculations, if you had 5 LTO5 drives and could get 120MB/s
from each drive - 30TB would take around 15 hours to clone and I'm not sure if
you could realistically get that kind of sustained throughput, and your full
backups would be even more problematic.
Another thing to bear in mind with the DD's, I believe that their file system
(and I'll probably get the terminology wrong here) is a sequential file system,
in that the more data that you write to them the wider the data is striped
across all the drives in the array, so initially performance will be slower, as
data is striped across only a few drives, but over time, as the DD increases
capacity, and data is spread across more drives, you should see a performance
increase (I could be wrong about this - but anecdotally it appears to be the
case from our observations)
Anyway .... hope that this helps
Mat
-----Original Message-----
From: EMC NetWorker discussion [mailto:NETWORKER AT LISTSERV.TEMPLE DOT EDU] On
Behalf Of Vishal Gupta
Sent: Saturday, 3 August 2013 1:36 AM
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Subject: [Networker] DD890 with daily Tape cloning
Hi Guys,
Brainstorming various possible config. with the following; Your inputs are
welcome please:
- NW 8.1 (WIN 2008)
- DD 890
- Daily incr (30TB)
- Weekly full (140TB)
Primary Plan:
The data will be backed up to DD (daily-incr; weekly-full) thru DDboost & then
to tape thru cloning DAILY.
Queries:
1. Is it an OK setup to go for wherein the data would go to DD thru DDboost &
then to tape thru cloning? Any implications? performance issues? recovery
issues?
2. Shall I go for DD as a VTL instead of DDboost & then do the cloning to tape.
Please Note: Cloning has to be done on a daily basis for tape off-siting
purposes.
~Vishal Gupta
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