Solved

SAN replication using all the bandwidth

Posted on 2009-07-15
6
528 Views
Last Modified: 2013-11-14
We have recently been having problems with bandwidth on a 1GB lan extension link between our office  and data centre.
The bandwidth used to average at about 2% - 10% but now averages at 35%+ with periodic bursts of over 100%.
 This is due to a new SAN that has been installed by an external company. They say that the SAN is permanently replicating and it is normal to use that amount of bandwidth.
 It is set to use up to 75% of available  bandwidth and that 35% is quite low.
Can someone confirm this is correct or even suggest a  solution other than get another link?
The links at the sites are 1gb into MDS switches.
0
Comment
Question by:andrewsmith950
  • 3
  • 2
6 Comments
 
LVL 55

Accepted Solution

by:
andyalder earned 175 total points
ID: 24867955
Site to site SAN replication can take a lot of bandwidth, for example if you use VMware and replicate the actual VMs and one is paging all that pagefile activity is unnecessarily replicated to the other site.
0
 
LVL 57

Assisted Solution

by:giltjr
giltjr earned 175 total points
ID: 24868703
The amount of bandwidth should be based on how much data you are writting to your SAN.

If  you are writing/updating a lot of data, then you will use a lot of bandwidth.

Based on your numbers (1 Gbps link with 35% utilization) that means you are doing about 300 Mbps which is about 37 MB per second.

If you were averaging 2-10% that means that you may have been doing 1-2MB per second before so the SAN replication added 35 MB per second.  What is your I/O rate to the local SAN.
0
 

Author Comment

by:andrewsmith950
ID: 24868831
1 gig
0
NAS Cloud Backup Strategies

This article explains backup scenarios when using network storage. We review the so-called “3-2-1 strategy” and summarize the methods you can use to send NAS data to the cloud

 
LVL 57

Expert Comment

by:giltjr
ID: 24869325
Are you saying you are updating 1 GB ps of data on your local SAN?

Or are you saying that the available bandwidth to your local SAN is only 1 Gbps?

What you need to look at is how much data per second do you update on your local SAN and then what you are replicating.  

As andyalder pointed out, there are somethings you should not be replicating, but you need to figure that out.

0
 

Author Closing Comment

by:andrewsmith950
ID: 31603934
Thanks . I don't know a lot about SANs so was just confirming what I was being told. Many thanks
0
 
LVL 57

Expert Comment

by:giltjr
ID: 24872022
Thanks.  

Just a little F.Y.I.  SAN are really nothing more than disk drives attached via a network.  Instead of Ethernet and IP as their lower level networking protocols they typically use Fiber Channel and have their own private physical network.  They also typically have much more bandwidth than LAN, which is what you typiclaly think of when here networking.
0

Featured Post

Microsoft Certification Exam 74-409

Veeam® is happy to provide the Microsoft community with a study guide prepared by MVP and MCT, Orin Thomas. This guide will take you through each of the exam objectives, helping you to prepare for and pass the examination.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

I had an issue with InstallShield not being able to use Computer Browser service on Windows Server 2012. Here is the solution I found.
The business world is becoming increasingly integrated with tech. It’s not just for a select few anymore — but what about if you have a small business? It may be easier than you think to integrate technology into your small business, and it’s likely…
This Micro Tutorial will teach you how to reformat your flash drive. Sometimes your flash drive may have issues carrying files so this will completely restore it to manufacturing settings. Make sure to backup all files before reformatting. This w…
Two types of users will appreciate AOMEI Backupper Pro: 1 - Those with PCIe drives (and haven't found cloning software that works on them). 2 - Those who want a fast clone of their boot drive (no re-boots needed) and it can clone your drive wh…

830 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question