<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div>On 3 Sep 2013, at 02:04, Elvis Dowson wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><meta http-equiv="Content-Type" content="text/html charset=iso-8859-1"><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hi,<div><br><div><div>On Sep 3, 2013, at 3:29 AM, Christian Gagneraud <<a href="mailto:chgans@gna.org">chgans@gna.org</a>> wrote:</div><br><blockquote type="cite"><blockquote type="cite">Isn't RAID-5 going to be slower, especially if it's software? RAID 1<br>is probably better as you'll potentially double the write speed to disk.<br>I use a couple of Vertex SSDs in RAID 1 giving a theoretical write speed<br>near to 1GBs. Write endurance is possibly a concern, but I've not had<br>any issues using them on a local build machine. I would probably look at<br>some higher end models if I was going to run a lot of builds. A lot less<br>noise than hard drives ;-)<br></blockquote><br>Thanks for the info, i will have a look at RAID-1, as you can see, I know absolutely nothing about RAID! ;)<br><br>Does SSD really help with disk throughput? Then what's the point of using ramdisk for TMPDIR/WORKDIR? If you "fully" work in RAM, the disk bottleneck shouldn't be such a problem anymore (basically, on disk, you should only have your yocto source tree and your download directory?).<br></blockquote></div><br></div><div>I use a Gigabyte Z77X-UP5TH motherboard </div><div><br></div><div><a href="http://www.gigabyte.us/press-center/news-page.aspx?nid=1166">http://www.gigabyte.us/press-center/news-page.aspx?nid=1166</a></div><div><br></div><div>which has support for RAID in BIOS, at boot up, and Thunderbolt connected to an Apple 27" Thunderbolt display. I've got two SSDs in a RAID1 configuration (striped).</div><div><br></div><div>If you can wait for some more time, they'll be releasing a version of the motherboard for the new haswell chips as well, but it's not probably going to increase performance. </div><div><br></div><div>I use a 3770K i7 quad-core processor, 16GB RAM, with a liquid cooled solution running at 3.8GHz. I've overclocked the CPU to 4.5GHz, but I end up shaving only 2 minutes off build times, so I just run it at 3.8GHz.</div><div><br></div><div>A core-image-minimal build takes around 22 minutes for me, for a Xilinx ZC702 machine configuration (Dual ARM Cortex A9 processor + FPGA).</div></div></blockquote><div><br></div><div>That's basically the spec I run (water cooling also keeps the noise down!). I generally get build times of just over 50 minutes for my system which has 'X' / GLES / Boost with something like 5500 tasks. Much better than the 10+ hours on a VM on the 4 year old MacBook Pro!</div><br><blockquote type="cite"><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><br></div><div>Here are the modifications that I've done to my system, to tweak SSD performance, for Ubuntu-12.10, for a RAID1 array.</div><div><br></div><div><div style="margin: 0px; font-size: 12px; font-family: 'Lucida Grande'; "><b>SSD performance tweaks (for non RAID0 arrays)</b></div><div style="margin: 0px; font-size: 12px; font-family: 'Lucida Grande'; min-height: 15px; "><br></div><div style="margin: 0px; font-size: 12px; font-family: 'Lucida Grande'; ">Step 01.01: Modify /etc/fstab.</div><div style="margin: 0px; font-size: 12px; font-family: 'Lucida Grande'; min-height: 15px; "><br></div><div style="margin: 0px; font-size: 12px; font-family: 'Lucida Grande'; ">$ sudo gedit /etc/fstab</div><div style="margin: 0px; font-size: 12px; font-family: 'Lucida Grande'; min-height: 15px; "><br></div><div style="margin: 0px; font-size: 12px; font-family: 'Lucida Grande'; ">Increase the life of the SSD by reducing how much the OS writes to the disk. If you don't need to knowwhen each file or directory was last accessed, add the following two options to the /etc/fstab file:</div><div style="margin: 0px; font-size: 12px; font-family: 'Lucida Grande'; min-height: 15px; "><br></div><div style="margin: 0px; font-size: 10px; font-family: Monaco; ">noatime, nodiratime</div><div style="margin: 0px; font-size: 12px; font-family: 'Lucida Grande'; min-height: 15px; "><br></div><div style="margin: 0px; font-size: 12px; font-family: 'Lucida Grande'; ">To enable TRIM support to help manage disk performance over the long term, add the following option to the /etc/fstab file:</div><div style="margin: 0px; font-size: 12px; font-family: 'Lucida Grande'; min-height: 15px; "><br></div><div style="margin: 0px; font-size: 10px; font-family: Monaco; ">discard</div><div style="margin: 0px; font-size: 12px; font-family: 'Lucida Grande'; min-height: 15px; "><br></div><div style="margin: 0px; font-size: 12px; font-family: 'Lucida Grande'; ">The /etc/fstab file should look like this:</div><div style="margin: 0px; font-size: 12px; font-family: 'Lucida Grande'; min-height: 15px; "><br></div><div style="margin: 0px; font-size: 10px; font-family: Monaco; "># / was on /dev/sda1 during installation</div><div style="margin: 0px; font-size: 10px; font-family: Monaco; ">UUID=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx / ext4 discard,noatime,nodiratime,errors=remount-ro 0 1</div><div style="margin: 0px; font-size: 12px; font-family: 'Lucida Grande'; min-height: 15px; "><br></div><div style="margin: 0px; font-size: 12px; font-family: 'Lucida Grande'; ">Move /tmp to RAM</div><div style="margin: 0px; font-size: 12px; font-family: 'Lucida Grande'; min-height: 15px; "><br></div><div style="margin: 0px; font-size: 10px; font-family: Monaco; "># Move /tmp to RAM</div><div style="margin: 0px; font-size: 10px; font-family: Monaco; ">none /tmp tmpfs defaults,noatime,nodiratime,noexec,nodev,nosuid 0 0</div><div style="margin: 0px; font-size: 12px; font-family: 'Lucida Grande'; min-height: 15px; "><br></div><div style="margin: 0px; font-size: 12px; font-family: 'Lucida Grande'; ">See: <a href="http://www.ocztechnologyforum.com/forum/showthread.php?82648-software-RAID-LVM-TRIM-support-on-Linux">Guide software RAID/LVM TRIM support on Linux</a> for more details.</div><div style="margin: 0px; font-size: 12px; font-family: 'Lucida Grande'; min-height: 15px; "><br></div><div style="margin: 0px; font-size: 12px; font-family: 'Lucida Grande'; ">Step 01.02: Move the browser's cache to a tmpfs in RAM</div><div style="margin: 0px; font-size: 12px; font-family: 'Lucida Grande'; min-height: 15px; "><br></div><div style="margin: 0px; font-size: 12px; font-family: 'Lucida Grande'; ">Launch firefox and type the following in the location bar:</div><div style="margin: 0px; font-size: 12px; font-family: 'Lucida Grande'; min-height: 15px; "><br></div><div style="margin: 0px; font-size: 10px; font-family: Monaco; "><a href="about:config">about:config</a></div><div style="margin: 0px; font-size: 12px; font-family: 'Lucida Grande'; min-height: 15px; "><br></div><div style="margin: 0px; font-size: 12px; font-family: 'Lucida Grande'; ">Right click and enter a new preference configution by selecting the New->String option.</div><div style="margin: 0px; font-size: 12px; font-family: 'Lucida Grande'; min-height: 15px; "><br></div><div style="margin: 0px; font-size: 10px; font-family: Monaco; ">Preference name: <span class="Apple-tab-span" style="white-space:pre"> </span>browser.cache.disk.parent_directory</div><div style="margin: 0px; font-size: 10px; font-family: Monaco; ">string value:<span class="Apple-tab-span" style="white-space:pre"> </span>/tmp/firefox-cache</div><div style="margin: 0px; font-size: 12px; font-family: 'Lucida Grande'; min-height: 15px; "><br></div><div style="margin: 0px; font-size: 12px; font-family: 'Lucida Grande'; ">See: <a href="http://brizoma.wordpress.com/2012/08/04/running-ubuntu-and-other-linux-flavors-on-an-ssd/">Running Ubuntu and other Linux flavors on an SSD « Brizoma</a>.</div><div style="margin: 0px; font-size: 12px; font-family: 'Lucida Grande'; min-height: 15px; "><br></div></div><div><br></div><div>Best regards,</div><div><br></div><div>Elvis Dowson</div></div></blockquote></div><br><div apple-content-edited="true">
<span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div>Chris Tapp</div><div><br></div><div><a href="mailto:opensource@keylevel.com">opensource@keylevel.com</a></div><div><a href="http://www.keylevel.com">www.keylevel.com</a></div><div><br></div></span><br class="Apple-interchange-newline">
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