<div dir="ltr">Alberto, take a close look at LIO or SCST as storage target servers. They offer a whole list of options and are very robust and more often than not iSCSI solution is a big part of the equation. Both LIO and SCST are kernel based solutions and extremely fast. Also take a close look at openindiana based solutions like nexenta store. </div>
<div class="gmail_extra"><br><br><div class="gmail_quote">On Wed, Mar 20, 2013 at 6:54 AM, Carlos Martín Sánchez <span dir="ltr"><<a href="mailto:cmartin@opennebula.org" target="_blank">cmartin@opennebula.org</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Thanks a lot Alberto, we really appreciate your taking the time to write this up. It's great to see the list becoming a knowledge base and not just a support list.<br clear="all">
<div>--<br>Carlos Martín, MSc<br>Project Engineer<br>
OpenNebula - The Open-source Solution for Data Center Virtualization<div><span style="border-collapse:collapse;color:rgb(136,136,136);font-family:arial,sans-serif;font-size:13px"><a href="http://www.OpenNebula.org" target="_blank">www.OpenNebula.org</a> | <a href="mailto:cmartin@opennebula.org" target="_blank">cmartin@opennebula.org</a> | <a href="http://twitter.com/opennebula" target="_blank">@OpenNebula</a></span><span style="border-collapse:collapse;color:rgb(136,136,136);font-family:arial,sans-serif;font-size:13px"><a href="mailto:cmartin@opennebula.org" style="color:rgb(42,93,176)" target="_blank"></a></span></div>
</div><div class="HOEnZb"><div class="h5">
<br><br><div class="gmail_quote">On Tue, Mar 19, 2013 at 1:58 PM, Alberto Zuin - Liste <span dir="ltr"><<a href="mailto:liste@albertozuin.eu" target="_blank">liste@albertozuin.eu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Just to share my experience.<br>
>From the beginning of my experience with OpenNebula, I made some changes in storage technology and now I found a solution that works pretty well for my necessities.<br>
First: there isn't an "always ok" solution, every solution works in a particular situation. My situation is, simply, a budget situation where the pourpose is saving money and have a solution that can fit my I/O load necessity.<br>
In my private cloud, I have 5 KVM servers and a total of 20-30 VM: some are computational only VM (mail scanner, DNS, ecc.), some are I/O intensive (MySQL server for LAMP, Syslog server, ecc.): the seconds are the problem because the previous solutions didn't fits the I/O necessities.<br>
My first solution was a storage server made with linux that exports an (c)LVM disk via AoE (just because has less overhead than iSCSI): the load of the server was very high and the I/O throughput not fast. Ok, the lesson I learned: if you have to make a shared storage, don't use a commodity server, use an optimized one with high speed disks, powerful controllers, 10GB Ethernet... or simply, buy a FC SAN ;-)<br>
My second test was with a cluster storage with MooseFS: here I had conflicting results. I have a customer with a well working setup with 10 storage server and 10 XEN Hypervisors; in my private cloud, with only 3 storage server (one master and two chunk) the I/O is slow as the first solution: no benefit from using two server to balance the I/O load, and 2 1 Gb Ethernet card in bonding is another bottleneck. The lesson I learned here: to have a powerful cluster storage you have to use many servers.<br>
My third (last) setup that work pretty well is... to not use only one shared storage, but distribute the storage across the hypervisors.<br>
I thought of a thing: my old hypervisors are some Dell R410 with 2 quad-core CPU and 32 GB Ram; if I can fit in a Rack 1U cabinet, 2 Mini-ITX Motherboard with a Core i7 (not perfectly like the Xeon of R410 but not too far) and 16 GB Ram... it's the same. And if I can fit also 4 high speed disk like WD Velociraptor for the data and two SSD disk for SO, I can use DRBD in Active/Active mode with cLVM or GFS2 to have a decent storage in HA for the VMs instantiated in this "double-server".<br>
Now I have 4 mini-itx double server each with this configuration; in OpenNebula, each double-server is a separate "cluster" and the DRBD disk is the datastore associated with the cluster.<br>
Certainly I can't migrate a VM across two cluster, but at the moment this solution fits pretty well my speed necessity, the costs of each "double-server" are less than a real 1U server and the power consumption in datacenter decreased.<br>
My 2 cents,<br>
Alberto<br>
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