Mads,

        CEPH is good indeed, but keep in mind that you should really be expert 
at this type of SDS. There are points that are not visible from the first look 
and may bring some unpleasent surprises.  For example: "default" option for 
storage I have tested was to make snapshots automatically from the files being 
saved to primary storage. As a consequence when you delete VM there are 
artifacts (snapshots) that are connect to deleted VM not being deleted by 
Cloudstack (since CS does not know they exist).  
               Another point - you can't directly use it as secondary storage. 
Need to set-up application server and run RadosGW. Performance - is a big 
question mark here. You need NFS or iSCSI anyway.
        What we haven't fully tested - disaster recovery or malfunction 
simulation. You must know how to recover from all types of the faults. It is 
very easy to lose everything by just doing wrong things (or in wrong order).  
From my point of view Ceph is rather complex to start together with CS. It may 
be easy to set up, but not so easy to manage. 
        Will suggest you to run it like a year at development to make yourself 
confident you can manage it. 

Regards,

Vadim.

-----Original Message-----
From: Mads Nordholm [mailto:[email protected]] 
Sent: Monday, March 02, 2015 8:16 PM
To: [email protected]
Subject: Re: Hardware question

Thanks a lot for your answer, Lucian. CEPH sounds like a very interesting 
solution. I will have to do some more research on that.

--
Mads Nordholm

On Tue, Mar 3, 2015 at 12:32 AM, Nux! <[email protected]> wrote:

> Hi Mads,
>
> Imo, if you want that flexibility you should go with non-local storage.
> CEPH is a popular choice here, but you will need 10 Gbps between 
> hypervisors and storage servers if you want reasonable performance.
> So, if you need more storage just add more CEPH servers. Need more 
> compute, add more hypervisors.
>
> HTH
> Lucian
>
> --
> Sent from the Delta quadrant using Borg technology!
>
> Nux!
> www.nux.ro
>
> ----- Original Message -----
> > From: "Mads Nordholm" <[email protected]>
> > To: [email protected]
> > Sent: Monday, 2 March, 2015 17:19:40
> > Subject: Hardware question
>
> > I am planning a small Cloudstack setup (using KVM for 
> > virtualisation)
> that
> > will allow me to run roughly 100 VPSs with these average requirements:
> >
> > - 1 core
> > - 512 MB RAM
> > - 20 GB SSD
> >
> > I am interested in input regarding a hardware configuration that 
> > will support this, and how to best build a small setup that will 
> > scale easily
> as
> > I grow. Within a year or so, I expect to have more than 1,000 guest
> running.
> >
> > I basically need a setup that will not completely break the bank as 
> > I
> start
> > out, but also one that will scale well as I grow. I am particularly 
> > concerned with being able to add only the resources I need. If I 
> > need
> more
> > storage, I want to be able to add only that (preferably just by 
> > adding disks to a RAID array), and if I need more computing power, I 
> > want to be able to add only that.
> >
> > Any input greatly appreciated.
> >
> > --
> > Mads Nordholm
>

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