Softlayer uses a SAN so the recovery is fast when a node fails but I am confused about guys like Rack-space which from reading look like they use local storage and not a block level access storage (ISCSI etc). How fast is the recovery if the hardware fails ? Any one offering VMWare-FT on a cloud ?

I need to stay away from Clustering, Snap Shot replication etc. The other options I am looking at are

1. Ever Run Mx
2. Stratus ftServer (Model 2600 is not expensive when you add up total cost)
3. Stratus also has Avance High-Availability Software

Jay

Im sure that people are offering FT vmware virtual machines. The reseller that i work for is also a VMWare service provider and we host customer VM's and can provide fault tolerant options, so i know its out there.

rackspace "cloud" has no failover, and no recovery. the harware fails it fails. It is just a VPS with a pretty gui.

rackspace "cloud" has no failover, and no recovery. the harware fails it fails. It is just a VPS with a pretty gui.

Yep, this is the big issue with all half the cloud providers. Every one will claim HA but then you read the SLA and find how they achieve HA

1. The best is the SAN option ....one box goes down, another box picks up the image

2. Worst is box goes down and the tech has to replace the mother board or take the drives and plug into another box.

When it comes to Vmware FT their are limitations, the big one is we can only use one core.

We are actually looking at buying the Stratus ftServer box.

Jay

Stuff like Stratus for web applications is overkill - great for legacy stuff that can't be made to scale horizontally or closed source apps. But if you've access to the source then you can with some effort make pretty much any web app scale horizontally and of course if it's your own code then you've no excuse :) Of course with the ability to scale horizontally comes your fault tolerance.

Stuff like Stratus for web applications is overkill - great for legacy stuff that can't be made to scale horizontally or closed source apps. But if you've access to the source then you can with some effort make pretty much any web app scale horizontally and of course if it's your own code then you've no excuse :) Of course with the ability to scale horizontally comes your fault tolerance.

True....but the cost of redevelopment, how long the app is going to be used etc etc.

We did a number crunching to find out if a MySQL Cluster is better or a Stratus FT running MySQL is better. When you bring in the cost of DBA with Cluster experience, leasing a hardware and its Tax advantages , apps usage etc etc.....Stratus won.

You can get a good system for around $700/month when it leased.

Jay

It's not a cloud if it doesn't have HA in my opinion. It's just marketing fluff.

Gigenet I think offers true cloud with no local storage and live migrate. I don't think they have monitoring to detect failure and automatically move your instance to a new node yet though.

So who have true cloud. Not FT but HA.

Did you have a look in the cloud offer section?

Did you have a look in the cloud offer section?

Yes every day ....and every one claim HA but explain the difference.

Yes every day ....and every one claim HA but explain the difference.

You are right, quite a few providers are claiming true HA and fault tolerance, but then you find they are lacking that somewhere in their infrastructure. Ie: does each server have multiple redundant ethernet links? Multiple redundant switches? SANs? Instant HA servers? Does any of this require human interaction?

Besides the hardware, the software infrastructure needs designed this way as well. True HA, Redundant Cloud's are still built with a little finesse in mind especially when you consider true vertical scaling.

Systems like stratus are a good way to combine non-cloud environments to do this, but a properly designed Cloud already does this without the need of additional external hardware, and adds many other benefits...

True....but the cost of redevelopment, how long the app is going to be used etc etc.

We did a number crunching to find out if a MySQL Cluster is better or a Stratus FT running MySQL is better. When you bring in the cost of DBA with Cluster experience, leasing a hardware and its Tax advantages , apps usage etc etc.....Stratus won.

You can get a good system for around $700/month when it leased.

Jay

A bit OT, but there are still some HA advantages that MySQL Cluster is going to provide over a Stratus FT setup running MyISAM or InnoDB, which can lead to higher overall uptime.

MySQL Cluster is the only MySQL storage engine that can take hot backups natively (i.e backups that don't affect the operating status of the database; using mysqldump requires a table lock where write transactions are halted). There was a commercial hot backup plugin for InnoDB offered by the company that invented the storage engine (InnoBase), but since it was acquired by Oracle, and Oracle acquired Sun (and therefore MySQL), it's now only available in the MySQL Enterprise package @ $5000 per year per server. You can also use LVM snapshots, which generally only take 5-10 seconds but still require a table lock in order to be consistent (which has lead to them being called "warm" backups).

Secondly, you can also perform version upgrades to MySQL Cluster without affecting database availability (a process called "rolling restart"), which you can't do with the other storage engines.