On 3 Sep 2013, at 02:04, Elvis Dowson wrote: > Hi, > > On Sep 3, 2013, at 3:29 AM, Christian Gagneraud <chg...@gna.org> wrote: > >>> Isn't RAID-5 going to be slower, especially if it's software? RAID 1 >>> is probably better as you'll potentially double the write speed to disk. >>> I use a couple of Vertex SSDs in RAID 1 giving a theoretical write speed >>> near to 1GBs. Write endurance is possibly a concern, but I've not had >>> any issues using them on a local build machine. I would probably look at >>> some higher end models if I was going to run a lot of builds. A lot less >>> noise than hard drives ;-) >> >> Thanks for the info, i will have a look at RAID-1, as you can see, I know >> absolutely nothing about RAID! ;) >> >> 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?). > > I use a Gigabyte Z77X-UP5TH motherboard > > http://www.gigabyte.us/press-center/news-page.aspx?nid=1166 > > 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). > > 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. > > 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. > > A core-image-minimal build takes around 22 minutes for me, for a Xilinx ZC702 > machine configuration (Dual ARM Cortex A9 processor + FPGA).
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! > > Here are the modifications that I've done to my system, to tweak SSD > performance, for Ubuntu-12.10, for a RAID1 array. > > SSD performance tweaks (for non RAID0 arrays) > > Step 01.01: Modify /etc/fstab. > > $ sudo gedit /etc/fstab > > 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: > > noatime, nodiratime > > To enable TRIM support to help manage disk performance over the long term, > add the following option to the /etc/fstab file: > > discard > > The /etc/fstab file should look like this: > > # / was on /dev/sda1 during installation > UUID=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx / ext4 > discard,noatime,nodiratime,errors=remount-ro 0 1 > > Move /tmp to RAM > > # Move /tmp to RAM > none /tmp tmpfs > defaults,noatime,nodiratime,noexec,nodev,nosuid 0 0 > > See: Guide software RAID/LVM TRIM support on Linux for more details. > > Step 01.02: Move the browser's cache to a tmpfs in RAM > > Launch firefox and type the following in the location bar: > > about:config > > Right click and enter a new preference configution by selecting the > New->String option. > > Preference name: browser.cache.disk.parent_directory > string value: /tmp/firefox-cache > > See: Running Ubuntu and other Linux flavors on an SSD « Brizoma. > > > Best regards, > > Elvis Dowson Chris Tapp opensou...@keylevel.com www.keylevel.com
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