<html><body bgcolor="#FFFFFF"><div>Sorry for the previous question of pound connections limit!</div><div>It caused by OS limit instead of Pound!</div><div><br></div><div><br></div><div>Thanks</div><div>Hugo Kuo <br><br>從我的 iPhone 傳送</div><div><br>"Reddin, Tim (Cloud Services)" <<a href="mailto:Tim.Reddin@hp.com">Tim.Reddin@hp.com</a>> 於 2011/9/20 上午12:24 寫道：<br><br></div><div></div><blockquote type="cite"><div><div class="WordSection1"><p class="MsoPlainText">Jay wrote:<o:p></o:p></p><p class="MsoPlainText"><o:p> </o:p></p><p class="MsoPlainText">>><o:p> </o:p></p><p class="MsoPlainText">FYI, some folks have done some performance testing of Glance with<o:p></o:p></p><p class="MsoPlainText">Swift backends. It was determined that using SSL caused a dramatic<o:p></o:p></p><p class="MsoPlainText">performance degradation (roughly decreased the network I/O throughput<o:p></o:p></p><p class="MsoPlainText">by half, with a queuing behvaiour showing up on GET requests as well.)<o:p></o:p></p><p class="MsoPlainText"><o:p> </o:p></p><p class="MsoPlainText">The solution was to disable zlib compression in SSL on the Glance API<o:p></o:p></p><p class="MsoPlainText">server box.<o:p></o:p></p><p class="MsoPlainText"><<<o:p> </o:p></p><p class="MsoPlainText"><o:p> </o:p></p><p class="MsoPlainText">Our initial tests used an image dervied from /dev/urandom which was an absolute worst case for compression.<br><br><o:p></o:p></p><p class="MsoPlainText">We found subsequently that using ZLIB with real images did provide “some” benefit (up to ~30 – but depends on image content). We also tried using LZO which gave up to 400% with a stock Ubuntu image (1.45GB). We will publish something on this when we have a more complete picture.<br><br>As Jay points out – replacing the compression algorithm is not easy.<br><br><br>Tim<o:p></o:p></p><p class="MsoPlainText"><o:p> </o:p></p><p class="MsoPlainText">-----Original Message-----<br>From: <a href="mailto:openstack-bounces+tim.reddin=hp.com@lists.launchpad.net">openstack-bounces+tim.reddin=hp.com@lists.launchpad.net</a> [mailto:openstack-bounces+tim.reddin=<a href="mailto:hp.com@lists.launchpad.net">hp.com@lists.launchpad.net</a>] On Behalf Of Jay Pipes<br>Sent: 19 September 2011 16:39<br>To: Kuo Hugo<br>Cc: <a href="mailto:openstack@lists.launchpad.net"><a href="mailto:openstack@lists.launchpad.net">openstack@lists.launchpad.net</a></a><br>Subject: Re: [Openstack] Load Balancers for Swift Proxy-servers ----why Pound ?<o:p></o:p></p><p class="MsoPlainText"><o:p> </o:p></p><p class="MsoPlainText">On Mon, Sep 19, 2011 at 7:47 AM, Kuo Hugo <<a href="mailto:tonytkdk@gmail.com">tonytkdk@gmail.com</a>> wrote:<o:p></o:p></p><p class="MsoPlainText">> btw , most of articles just using HTTP instead of HTTPS. Does Pound better<o:p></o:p></p><p class="MsoPlainText">> than Nginx under HTTPS?<o:p></o:p></p><p class="MsoPlainText"><o:p> </o:p></p><p class="MsoPlainText">FYI, some folks have done some performance testing of Glance with<o:p></o:p></p><p class="MsoPlainText">Swift backends. It was determined that using SSL caused a dramatic<o:p></o:p></p><p class="MsoPlainText">performance degradation (roughly decreased the network I/O throughput<o:p></o:p></p><p class="MsoPlainText">by half, with a queuing behvaiour showing up on GET requests as well.)<o:p></o:p></p><p class="MsoPlainText"><o:p> </o:p></p><p class="MsoPlainText">The solution was to disable zlib compression in SSL on the Glance API<o:p></o:p></p><p class="MsoPlainText">server box.<o:p></o:p></p><p class="MsoPlainText"><o:p> </o:p></p><p class="MsoPlainText">There aren't a whole lot of easy ways to do this in OpenSSL 0.9.8, but<o:p></o:p></p><p class="MsoPlainText">you may find the discussion in this article interesting:<o:p></o:p></p><p class="MsoPlainText"><o:p> </o:p></p><p class="MsoPlainText"><a href="http://journal.paul.querna.org/articles/2011/04/05/openssl-memory-use/">http://journal.paul.querna.org/articles/2011/04/05/openssl-memory-use/</a><o:p></o:p></p><p class="MsoPlainText"><o:p> </o:p></p><p class="MsoPlainText">Cheers,<o:p></o:p></p><p class="MsoPlainText">jay<o:p></o:p></p><p class="MsoPlainText"><o:p> </o:p></p><p class="MsoPlainText">_______________________________________________<o:p></o:p></p><p class="MsoPlainText">Mailing list: <a href="https://launchpad.net/~openstack"><a href="https://launchpad.net/~openstack">https://launchpad.net/~openstack</a></a><o:p></o:p></p><p class="MsoPlainText">Post to : <a href="mailto:openstack@lists.launchpad.net"><a href="mailto:openstack@lists.launchpad.net">openstack@lists.launchpad.net</a></a><o:p></o:p></p><p class="MsoPlainText">Unsubscribe : <a href="https://launchpad.net/~openstack"><a href="https://launchpad.net/~openstack">https://launchpad.net/~openstack</a></a><o:p></o:p></p><p class="MsoPlainText">More help : <a href="https://help.launchpad.net/ListHelp"><a href="https://help.launchpad.net/ListHelp">https://help.launchpad.net/ListHelp</a></a><o:p></o:p></p></div></div></blockquote></body></html>