<div dir="ltr">Hi.<br><br><div class="gmail_quote"><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div class="Ih2E3d"><br>
</div>I will try. Shared block storage is a block device like /dev/sda<br>
accessible on more than one server at once. This may be a plain hard-disk<br>
or a hardware RAID. Coordination among the servers is handled on the file<br>
system level above that - for example by OCFS or GFS. Using a normal file<br>
system like Ext3 is not possible for read/write operations to the same<br>
shared block storage since the servers would get very confused.<br>
<div class="Ih2E3d"></div></blockquote><div><br>Thanks for the info.<br> </div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">As far as I know; Lustre in itself do not handle redundancy or fault<br>
tolerance. In order to get redundancy for Lustre (unlike GlusterFS or<br>
Ceph) that must be handled by some kind of shared storage. And Lustre<br>
needs the data to be stored on a block device.<br>
<br>
Using shared block storage to keep the data on (usually a hardware RAID on<br>
a SAN) makes it to move the service from one physical server to another.<br>
<br>
Example: normally one server is taking care of service A and another<br>
server is taking care of service B. The first server is also passively<br>
taking care of service B and the other server passively taking care of<br>
service A. When the first server goes down the other server is taking over<br>
service A, which means both A and B are located on the same server.<br>
<div><div></div><div class="Wj3C7c"></div></div></blockquote><div><br>So basically the data stored on 2 nodes, but their coordination requires a shared block device? Because they do seem to speak about specific storage nodes - but I might not understand this correctly.<br>
<br>Regards.<br></div></div></div>