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Re: Reliable Cloud host ?
From: Jimmy Hess <mysidia () gmail com>
Date: Thu, 1 Mar 2012 01:23:24 -0600

On Mon, Feb 27, 2012 at 7:03 PM, George Herbert
<george.herbert () gmail com> wrote:
On Mon, Feb 27, 2012 at 3:45 PM, William Herrin <bill () herrin us> wrote:
universe does $30/mo per customer recover that cost during the useful
life of the equipment?
As I stated, one can either do it with SANs or with alternate storage.

Should not assume Rackspace et. all  provide any level of fault
tolerance for extraordinary situations such as hardware failure beyond
what they have promised or advertised. IaaS provided redundancy is not
always necessary, and may be unwanted in various situations due to its
cost;  single redundancy means a minimum of twice the cost of
non-redundant (plus the overhead of failover coordination).   With
various computing applications it  may make a great deal of sense to
handle in software --  should a node fail,  the software can detect a
node failed, eject it,  reassign its unfinished work units later.

Typical Enterprise level fault tolerant SAN manufacturer prices seen
are   ~ $12 to $15/GB usable storage, for ~50 IOPS/TB, data mostly at
rest, and SAN equipment has a useful lifetime of 5-6 years; a typical
200gb  server then exceeds  $30/month in  intrinsic FT SAN hardware
cost.

There IS a place for IaaS providers to sell such product, probably  at
four or five times the $/month for a typical server.     Just like
there is a place for Network service providers to sell transport and
network access products  that have redundancy built into the product,
such as protected circuits,  multiple-port,    dual WAN ,  that can
sustain any single router failure, etc.
Those network products still can't reliably guarantee 100% uptime for
the service.


There is a place for IaaS providers to sell products where  they do
NOT promise a level of reliability/fault tolerance or performance
guarantee that requires them to
utilize an Enterprise FC SAN or similar solution.

  Just like there is a place for NSPs to sell transport and network
access products that  will fail if
a single router,  card, port fails, or if there is a single fiber
break  or  erroneously unplugged cable.


This way the end user can save on their network connectivity costs;  a
tradeoff based on the impact of the difference between their network
with  1% downtime and their network with   0.001% downtime;  VERSUS
the impact of the cost difference between those two options.

End users may also prefer to implement their redundancy through
dual-homing via multiple providers.


It is very important that the end user and the provider's sales/marketing
know  exactly which kind of product each offering is.


 Amazon hit those price points with a custom distributed filesystem
that's more akin to the research distributed filesystems than anything

Amazon is quite unique;  developing a custom distributed filesystem is a rather
extraordinary measure,  that provides  them an  advantage when selling certain
services.

But   even EC2 instance storage is not guaranteed.    The instance
storage is scratch space
If your instance becomes degraded, and you need to restart it,  what you get is
a "clean" instance,  matching the original image.

EBS and S3 are another matter.

The same provider that offers some  'unprotected'  services,  may also
offer some more expensive storage services that have greater protections.



--
-JH


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