<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<style type="text/css" style="display:none;"><!-- P {margin-top:0;margin-bottom:0;} --></style>
</head>
<body dir="ltr">
<div id="divtagdefaultwrapper" style="font-size:12pt;color:#000000;font-family:Calibri,Helvetica,sans-serif;" dir="ltr">
<p>Ok, the 40Gb NIC that I got were for free. But anyway, if you were working with 6 HDD + 1 SSD per server, then you get 21 disks on your cluster. As data in a JBOD will be built all over the network, then it can be really intensive especially depending on
the number of replicas you choose for your needs. Also, when moving a VM alive you must transfer the memory contents of a VM to another node (just think about moving a VM with 32GB RAM). All together, it can be a quite large chunk of data moving over the network
all the time. While 40Gb NIC is not a "must", I think it is more affordable as it cost much less then a good disk controller.</p>
<p><br>
</p>
<p>But my confusion is that, as said by other fellows, the best "performance model" is when you use a hardware RAIDed brick (i.e.: 5 or 6) to assemble your GlusterFS. In this case, as I would have to buy a good controller but have less network traffic, to lower
the cost I would then use a separate network made of 10Gb NICs plus the controller.</p>
<p><br>
</p>
<p>Moacir<br>
</p>
<div style="color: rgb(49, 55, 57);"><font size="2"><span style="font-size:10pt;">
<div class="PlainText"><br>
<br>
<br>
><br>
> > Le 8 ao?t 2017 ? 04:08, FERNANDO FREDIANI <fernando.frediani@upx.com> a<br>
> ?crit :<br>
><br>
> > Even if you have a Hardware RAID Controller with Writeback cache you<br>
> will have a significant performance penalty and may not fully use all the<br>
> resources you mentioned you have.<br>
> ><br>
><br>
> Nope again,from my experience with HP Smart Array and write back cache,<br>
> write, that goes in the cache, are even faster that read that must goes to<br>
> the disks. of course if the write are too fast and to big, they will over<br>
> overflow the cache. But on todays controller they are multi-gigabyte cache,<br>
> you must write a lot to fill them. And if you can afford 40Gb card, you can<br>
> afford decent controller.<br>
><br>
<br>
The last sentence raises an excellent point: balance your resources. Don't<br>
spend a fortune on one component while another will end up being your<br>
bottleneck.<br>
Storage is usually the slowest link in the chain. I personally believe that<br>
spending the money on NVMe drives makes more sense than 40Gb (except [1],<br>
which is suspiciously cheap!)<br>
<br>
Y.<br>
[1] <a href="http://a.co/4hsCTqG" id="LPlnk802834" previewremoved="true">http://a.co/4hsCTqG</a><br>
<br>
</div>
</span></font></div>
</div>
</body>
</html>