<div dir="ltr"><div class="gmail_default" style="font-family:monospace,monospace"><br></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Feb 23, 2017 at 7:18 PM, Zhenyu Zheng <span dir="ltr"><<a href="mailto:zhengzhenyulixi@gmail.com" target="_blank">zhengzhenyulixi@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">Matt,<div><br></div><div>Thanks for the information, I will check that; But still I think the user demand here is to use local disk from</div><div>compute node as block device, as the data can be remained if the old vm got deleted, and we can start a</div><div>new one with the data and having the performance they wanted.</div><div><br></div><div>Kevin Zheng</div></div><div class="gmail-m_-1661954653425188530HOEnZb"><div class="gmail-m_-1661954653425188530h5"><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Feb 24, 2017 at 4:06 AM, Matt Riedemann <span dir="ltr"><<a href="mailto:mriedem@linux.vnet.ibm.com" target="_blank">mriedem@linux.vnet.ibm.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><span>On 9/26/2016 9:21 PM, Zhenyu Zheng wrote:<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
Hi,<br>
<br>
Thanks for the reply, actually approach one is not we are looking for,<br>
our demands is to attach the real physical volume from compute node to VMs,<br>
by this way we can achieve the performance we need for usecases such as<br>
big data, this can be done by cinder using BlockDeviceDriver, it is quite<br>
different from the approach one you mentioned. The only problem now is<br>
that we cannot practially ensure the compute resource located on the same<br>
host with the volume, as Matt mentioned above, currently we have to<br>
arrange 1:1 AZ in Cinder and Nova to do this and it is not practical in<br>
commercial<br>
deployments.<br>
<br>
Thanks.<br>
<br>
</blockquote>
<br></span>
Kevin,<br>
<br>
Is the issue because you can't use ephemeral local disks (it must be a persistent boot from volume)?<br>
<br>
Have you looked at using the LVM image backend for local storage in Nova? I thought cfriesen said once that windriver is doing high performance config using local LVM in nova.<span class="gmail-m_-1661954653425188530m_-4984656849189986875HOEnZb"><font color="#888888"><br>
<br>
-- <br>
<br>
Thanks,<br>
<br>
Matt Riedemann</font></span><div class="gmail-m_-1661954653425188530m_-4984656849189986875HOEnZb"><div class="gmail-m_-1661954653425188530m_-4984656849189986875h5"><br>
<br>
<br>
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<br></blockquote></div><div class="gmail_default" style="font-family:monospace,monospace">Hi Kevin,</div><div class="gmail_default" style="font-family:monospace,monospace"><br></div><div class="gmail_default" style="font-family:monospace,monospace">Few things that may be related to your request:</div><div class="gmail_default" style="font-family:monospace,monospace"><br></div><div class="gmail_default" style="font-family:monospace,monospace">>>"<span style="font-size:12.8px;font-family:arial,sans-serif">our demands is to attach the real physical volume from compute node to VMs"</span></div><div class="gmail_default" style="font-family:monospace,monospace"><span style="font-size:12.8px;font-family:arial,sans-serif"><br></span></div><div class="gmail_default" style="font-family:monospace,monospace">Cinder had this capability for a while in the form of the block-driver, but it's been removed due to lack of functionality, testing and really interest all the way around. We also took a look at performance data and the fact was that the performance between iSCSI over a 10Gig dedicated network and a local block device was minimal. The block-driver model breaks just about every Cinder feature at this point so rather than carry it around as a special one off case it's been removed and if you really need local disk to the compute node, you need to just use the ephemeral LVM driver in Nova. </div><br></div><div class="gmail_extra"><div class="gmail_default" style="font-family:monospace,monospace">>>"<span style="font-size:12.8px;font-family:arial,sans-serif">compute node as block device, as the data can be remained if the old vm got deleted"</span></div><div class="gmail_default" style="font-family:monospace,monospace"><br></div><div class="gmail_default" style="font-family:monospace,monospace">Yes, I understand what you are asking for here, and that's similar to how the old block-driver worked; like I said though that's been deprecated and removed. I would be curious to get more info about the *requirement* here in terms of performance. We had a number of people look at the performance characteristics between a Cinder LVM Volume behind an LIO Tgt and found there to be minimal differences in performance between the raw disk device without iSCSI.</div><div class="gmail_default" style="font-family:monospace,monospace"><br></div><div class="gmail_default" style="font-family:monospace,monospace">There are ways to bring the block-driver up to feature parity etc, but frankly most have decided it's not worth it as there's very little real benefit to using it over the existing and well supported drivers.</div><div class="gmail_default" style="font-family:monospace,monospace"><br></div><div class="gmail_default" style="font-family:monospace,monospace">Thanks,</div><div class="gmail_default" style="font-family:monospace,monospace">John</div><br></div></div>