On 06/28/2010 01:28 PM, ESGLinux wrote:
2010/6/28 Gordan Bobic <gordan@xxxxxxxxxx <mailto:gordan@xxxxxxxxxx>>
On 06/28/2010 12:26 PM, ESGLinux wrote:
2010/6/28 Gordan Bobic <gordan@xxxxxxxxxx
<mailto:gordan@xxxxxxxxxx> <mailto:gordan@xxxxxxxxxx
<mailto:gordan@xxxxxxxxxx>>>
On 06/28/2010 11:11 AM, ESGLinux wrote:
Hi All,
I´m going to mount an active-active file server and my first
idea is to
mount a NFS service with luci but now I have the doubt
if is it
possible. with luci i have allways mounted Active-Passive
services. So,
my question is that.
Any other aproach to get an Active-Active file Server?
Not with NFS, since NFS has no feature to have multiple
servers/share. But there is no reason you can't connect half
of the
clients to the other server.
I haven't realized about it, it could be a solution.
one thing, I have been investigating about it, and I have
thought it
could be possible using Linux Virtual Server (administered with
piranha), what do you think about it?
I think you need to start to list your requirements in a coherent
manner first, in terms of performance, features, and redundancy. The
solution you should be looking for will be more obvious then.
Hi again,
you are right this is a bit confusing (my customer said me: I need a
cluster file server, its your problem... :-/ ). Now I´m investigating
how to do it.
what basically I need is:
I need to access the files in HA and it must be scalable. If the load is
a problem I could be able to add another node to solve the load problem,
(so I thought in a Active-active, because with Active-Pasive only there
is one node active so the load problem is still there)
Whether it will scale is dependant almost exclusively on your access
pattern. If you can group your cluster file system accesses so that
nodes hardly ever access the same file system subtrees then it will
scale reasonably well. If you are going to have nodes randomly accessing
the file system paths, then the performance will take a nosedive, and
get progressively slower as you add nodes.
This will scale linearly:
Node 1 accessing /my/path/1/whatever
Node 2 accessing /my/path/2/whatever
This will scale inversely (get slower):
Node 1 accessing /my/path
Node 2 accessing /my/path
Cluster file systems are generally slower at random access than
standalone file systems, so you are likely to find that having a
standalone failover (active-passive) solution is faster than a clustered
active-active solution, especially as you add nodes.
So the question really comes down to access patterns. If you are going
to have random access to lots of small files (e.g. Maildir), the
performance will be poor to start with and get worse as you add nodes
unless you can engineer your solution so that access for a particular
subtree always hits the same node. OTOH for large file operations, the
bandwidth will be more dominant than random access lock acquisition
time, so the performance will be OK and scale reasonably as you add nodes.
Note that this isn't something specific to GFS - pretty much all cluster
file systems behave this way.
Gordan
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