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Support Applying acceleration without understanding the application is a high risk, wasteful strategy. What’s the point of accelerating non-business critical traffic and diminishing the performance of VoIP and ERP in favour of Doom? How many IT Managers would be well regarded for such an action?
Applying acceleration without understanding the application is a high risk, wasteful strategy. What’s the point of accelerating non-business critical traffic and diminishing the performance of VoIP and ERP in favour of Doom? How many IT Managers would be well regarded for such an action?
It is like most things, if you can’t measure it, you can’t make reasonable decisions and apply controls.
The next issue is how you apply acceleration. You can’t use the same techniques for all traffic types and expect to get optimal results across the board. Bulk transfers, like CIFS and NFS traffic is best handled by disk based compression and reduction techniques, but transactional or real time data like VoIP and video is better handled in memory on a real time operating system. So multiple systems are needed to handle the different acceleration technologies for optimal results on the different traffic types.
Then there is the issue of QoS. This is one of those terms that means so many different things to so many people. The marketing people have a field day. They say QoS and everybody puts their own interpretation on it. In reality:
You can’t have sensible QoS and queues. With queues eventually packets will be thrown away and if that is the only control mechanism you have then you are bound to end up with congestion and retransmission.
• You can’t have sensible QoS without a deep layer 7 understanding of the application - not all port 80 traffic is created equal – the ERP traffic is probably more important than browsing the favourite football site (perhaps?)
• You can’t have sensible QoS without control of inbound as well as outbound traffic. Most WAN links are over subscribed – a head office with a 20Mbps line and 20 branch offices with 2Mbps lines has a problem, what is the point of the branch office sending the packets to the head office, for the over subscribed link there to just throw the packets away. You need to not send them in the first place until the head office is in a position to receive them; otherwise you just retransmit and make the whole situation worse.
Acceleration is more than just stuffing packets down a pipe as quickly as possible; to do it right needs an intelligent solution that applies the right technologies to the right applications. After all, delivery of the application is the reason for having the network in the first place, so using a shotgun rather than a needle may give results, but perhaps not the best results if you are trying to remove a splinter from your finger!!!
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If “stuff” was all created equal life would be a lot easier, but life is not like that. You have file data and application data. Most application data is block based, while file data, perhaps not surprisingly, is file based (i.e. not block based). The differentiation is one of the major differences between SAN and NAS. SANs provide block based storage and NAS provides file based. That’s a pain, so you need a NAS box for files and a SAN for applications, that’s two lots of storage to manage. It would be so much easier if everything could be in one place.
There are two approaches to a workaround:
- You can put in a SAN to provide block capacity and then carve off some of that space and assign it to a NAS gateway device. These can often give enhanced management features for the file data, such as replication and snapshot, but there are usually two management interfaces, one for the SAN and one for the NAS gateway.
- You can use a suitable NAS box which provides suitable connectivity and allows you to allocate some volumes to SAN (block based). Some might argue that you take a performance hit on the SAN space because you don’t have direct access to the disk, but in most cases that is pretty negligible and is usually easily outweighed by the benefits of universal replication and snapshots through a single management interface for both block and file capacity.
If you look at the agámi stuff you will see it provides blistering performance, serving more than 1GBps (that is gigabyte, not bit). It allows for things like over 1,000 snapshots per file system (NAS) or volume (SAN) as well as replication of both data types either synchronously or asynchronously.
Not only is it screamingly fast, it is (relatively) cost effective when compared to others in the market and more compact and uses less electricity, so making it cheaper to run. It is not often in our industry you find something faster, smaller, cheaper and more cost effective (but still with a decent pedigree) that the dominant market leaders, but this might well be the one.
http://www.solutioncentre.co.uk/info/agami/
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New features include:
Support for Windows 2000 virtual servers – enabling consolidation of the vast majority of deployed Windows server workloads.
Multi-processor support (SMP) for Windows Server 2003 and Windows XP guests – delivering scalable virtualization of Exchange, SQL Server, and other multi-threaded and compute-intensive applications.
Improved Windows guest support – providing accelerated network performance, ability to suspend/resume virtual machines, up to 8GB RAM per Windows guest, and signed drivers with WHQL certification.
iSCSI SAN support – delivering affordable networked storage support.
VLAN trunk support for virtual bridges – providing network traffic isolation.
CPU, memory, disk and network resource control – enabling IT organizations to deliver more server resources to the highest-priority workloads.
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If it hasn’t happened to you (yet) you have heard the stories, the application server crashes and when the server comes back up, the application doesn’t.
Presumably the point of replicating data is that the replicated data is useful. For flat files that is not a big deal, the file is there or not. For application data that is a whole different issue.
The problem is applications have multiple files to update – database, log, index, etc and they have buffers, so the most recent data for one of those files might not be on disk, but in a buffer, so if you just replicate what is on the disk you don’t have a consistent recoverable state.
The reality is just sending and applying all changes in the exact order that they occurred on the production system, does not guarantee a crash -consistent copy of data on the secondary system. If that was enough, then the server crash would not be a problem. The only way to do that is to quiesce the application and flush the buffers to disk.
It could be you are lucky and the application is robust enough to recover from any inconsistencies, but are you prepared to bet the company (and your job) on it?
So you have a choice, write order replication and perhaps have to spend the time running some sort of application recovery process, but if you get it back then you have (hopefully) negligible data loss. Alternatively, use a mechanism to ensure application recovery without hassle and lose a bit of data. There is a trade off between RTO and RPO and you need to work out what is important in your environment.
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Managing change is an issue many of our clients are facing. We have been working with an organisation called Solidcore to deliver closed loop change control and security to server, workstation, network and database installations. The intrinsic problem with most change control systems are they are open loops and therefore uncontrolled.
The S3 product consists of a client application that installs on each server, once activated this prevents any and all changes to the server. A server manages and monitors all the servers and provides central management and reporting.
The Server software can be integrated into help desk/change control/remediation services to tie support tickets to change control for example.
So…
What does it look like?
On the servers running the client there is little or nothing to see, at least until you try and change something. Below is the message we receive when trying to delete the dialer.exe file in the C:\Windows directory.
As you can see, I am denied access from deleting the file. On the server I see the following:
So I tried to delete the file several times, so you can see that I get an alert each time someone tries to change/delete/rename/overwrite a file.
Obviously, there are times when you actually want to update your servers.
Below is the screen where I allow updates to a server:
You can see the padlock there showing that the box is presently secured. That changes to an open padlock once you click YES. This sort of task can be tied to your helpdesk solution.
S3 Control records all changes and attempted changes in a secure format, which can’t be altered, so helps address your compliance issues. This also helps with fault finding as looking through a centralised record of all changes is much easier than trying to work through system logs trying to work out what may have happened or affected the system or application, who was involved, etc.
For more info click here...
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