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Re: Cloud hosting - good groups or forums?

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On 22/05/15 00:07, The Natural Philosopher wrote:

>
> Well that depends on how fast the data is changing and what bandwidth
> you have.

It could be as much as 6TB in one day if one of the larger machines hits 
a full backup cycle (which is every 4 weeks - we do not trust 
incrementals without a periodic refresh).

The offsite backup system I have now (with the disks and linux head 
nodes) live sin my building. It survives OK on a gigabit fibre building 
link to the rest of the college.

We had that fibre chopped by workmen repairing the pavement the other 
month and it was an observable fact that the backups could not cope 
using the building's 100mbit/s backup link. They could not even manage a 
full daily run inside a day.

> I mean how is the data going to get ON the machine in the first place?
> Presumably you will have it somewhere else so can just 'preload' the
> backup with it when you load the server.

Direct transfer from the existing system.

>
> Then rsync just tracks the changes.

rsync is not the correct solution here - well, it could be part of the 
solution - rsnapshot makes for a nice way to offer per-file retrieval.

But with a large virtual system, you need an efficient disaster recovery 
mechanism which means block level.

The other thing is it is unlikely with a forthcoming building move that 
I will have anywhere to house the backup system, so it will have to go 
in a datacentre too. On the plus side, if the hosting company provide it:

1) If the kit blows up, they get to do the restoration;

2) It does not count as chargeable bandwidth.


>
>> On eof the driving factors with you have a lot of VMs is being able to
>> get from the backup to running VMs quickly in the event of a disaster
>> ("disaster" might include needing to revert a VM that boned itself).
>>
>
> Mmm. Sounds like what you would need is a different physical backup
> server in the same location with uber high bandwidth between it and the
> VMS that do the work

Indeed - gigabit min, and that would take a week to do a full DR 
restoration. 10 gig would be ideal, but OTT. We are academic, so a tiny 
risk of disaster can be balanced against being offline for 1,2,3 weeks - 
which would be out of the question if we were a commercial entity.

The important thing is that we still have the means to recover, rather 
than how long it takes (within reason).

> Look its just a thought, but at the sort of level you are running, maybe
> a pair of blade chassis, with a humongous RAID on each that are yours to
> own in a given data centre is in fact a solution.

Our current system is (not commercially sensitive):

4 Dell R610s with 2 CPU sockets (12 cores total) and 192GB RAM.
1 EqualLogic PS6500e iSCSI SAN with 48 x 1TB SATA disks
1 EqualLogic PS4100x iSCSI SAN with 24 x 600GB 10k SAS disks
Pair of stacked gig switches to interlink.

It's quite a decent system - runs 180 VMs quite happily on 3 of 4 hosts 
to allow maintenance and failure.

It's tiny compared to HPC setups used by the likes of the particle 
physics guys (Those can number 100s of 1U nodes and petabytes of storage 
interconnected with insane (multiple 10's gig) networking.

> Rackspace and a shitload of internet bandwidth might be less than 20 k a
> year for a pair of big blades.

> And you could shove a couple of fibres between em to do the backups.
>
> A lotta capital though - tens of thousands. But this has to be an earner
> or you wouldn't be taking it this far as it is.

A bit more than that :)

But that's OK - this setup earns its income - that's why it had to be 
professional, well sourced and reliable to maintain long term reputation.

There's no question of doing this on the cheap. If I replicated the 
current system, it would be the one above but with 50% capacity added to 
everything. But I am extremely interested in VMWare's vSAN as I could 
lose the SANs (expensive) in favour of more nodes carrying their own 
storage. vSAN aggregates this cluster wide and provides fault resilience 
(think Google Filesystem - similar idea).


The thing that caught me out is that outsourcing this as a virtual 
datacentre is SO much more expensive (5x ish it seems). I would perhaps 
expected double the cost. OK those guys do all the hardware and 
networking, but OTOH they can share multiple customers on very large 
clusters which allows diversity to be factored in.

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Thread

Cloud hosting - good groups or forums? Tim Watts <tw_usenet@dionic.net> - 2015-05-19 21:53 +0100
  Re: Cloud hosting - good groups or forums? noydb@no.way (Bruce Sinclair) - 2015-05-19 23:05 +0000
    Re: Cloud hosting - good groups or forums? Tim Watts <tw_usenet@dionic.net> - 2015-05-20 07:55 +0100
      Re: Cloud hosting - good groups or forums? Tim Watts <tw_usenet@dionic.net> - 2015-05-20 08:14 +0100
        Re: Cloud hosting - good groups or forums? The Natural Philosopher <tnp@invalid.invalid> - 2015-05-20 09:26 +0100
          Re: Cloud hosting - good groups or forums? Tim Watts <tw_usenet@dionic.net> - 2015-05-20 10:26 +0100
        Re: Cloud hosting - good groups or forums? Joe Beanfish <joebeanfish@nospam.duh> - 2015-05-20 13:44 +0000
          Re: Cloud hosting - good groups or forums? Tim Watts <tw_usenet@dionic.net> - 2015-05-20 15:31 +0100
    Re: Cloud hosting - good groups or forums? Tim Watts <tw_usenet@dionic.net> - 2015-05-20 13:06 +0100
  Re: Cloud hosting - good groups or forums? Tim Watts <tw_usenet@dionic.net> - 2015-05-20 08:46 +0100
  Re: Cloud hosting - good groups or forums? Tim Watts <tw_usenet@dionic.net> - 2015-05-21 11:11 +0100
    Re: Cloud hosting - good groups or forums? Marc Haber <mh+usenetspam1118@zugschl.us> - 2015-05-21 12:27 +0200
      Re: Cloud hosting - good groups or forums? Tim Watts <tw_usenet@dionic.net> - 2015-05-21 14:52 +0100
        Re: Cloud hosting - good groups or forums? The Natural Philosopher <tnp@invalid.invalid> - 2015-05-21 22:51 +0100
          Re: Cloud hosting - good groups or forums? Tim Watts <tw_usenet@dionic.net> - 2015-05-21 23:57 +0100
            Re: Cloud hosting - good groups or forums? The Natural Philosopher <tnp@invalid.invalid> - 2015-05-22 00:07 +0100
              Re: Cloud hosting - good groups or forums? Tim Watts <tw_usenet@dionic.net> - 2015-05-22 08:54 +0100

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