always create the locations that need frequent I/O /home, swap on the outer tracks ?
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From: annalissa on 17 Jul 2010 06:38 Hi all, The following is what i have read in a magazine named "linux for you" , To what extent this is true ? The general rule is that you should always create the locations that need frequent I/O -/home, swap on the outer tracks , the easiest way to achieve this is to create these partitions first when partitioning your hard disk ? Reason all modern H.D.D's use a concept called ZCAV(zonal constant angular velocity). this takes advantage of the fact that more linear space is available on the outer tracks of the disk platter rather than on the inside tracks. now since the disk spins at a constant rate , which is also known as CAV (constant angular velocity) the read/write I/O speed will be greater at the outer tracks as compared to the inner tracks
From: Aragorn on 17 Jul 2010 07:27
On Saturday 17 July 2010 12:38 in comp.os.linux.setup, somebody identifying as annalissa wrote... > Hi all, > > The following is what i have read in a magazine named "linux for > you" , To what extent this is true ? > > The general rule is that you should always create the locations that > need frequent I/O -/home, swap on the outer tracks , the easiest way > to achieve this is to create these partitions first when partitioning > your hard disk ? > > Reason all modern H.D.D's use a concept called ZCAV(zonal constant > angular velocity). this takes advantage of the fact that more linear > space is available on the outer tracks of the disk platter rather than > on the inside tracks. now since the disk spins at a constant rate , > which is also known as CAV (constant angular velocity) the read/write > I/O speed will be greater at the outer tracks as compared to the inner > tracks While the above is true, I don't think that there would be a significant performance impact if you happen to have the filesystems with the most frequent I/O closer to the spindle. It will be measurable via benchmarks, yes, but whether you will actually notice it as a user is something I tend to question. ;-) There are also a few other considerations if you want to take that article serious, i.e. if your system has a lot of RAM, then you will most likely not be using swap at all, or only under very rare circumstances. Next to that, "/usr" is a filesystem which is primarily read-only, so it will under normal circumstances not be written to - I myself always have "/boot", "/usr" and "/opt" mounted read-only during normal operation - but just because it's not being written to does not mean it's not being read. "/usr" is where the bulk of the software is installed - technically: everything that is required for multi-user operation. "/opt" is similar, except that it's for optional software, i.e. software which does not integrate well with the "/usr" hierarchy and may have been added on later. "/usr/local" shares a similar purpose as "/opt" but is intended for software which was installed from sources by the sysadmin, as opposed to software in binary form supplied via the distribution-specific package manager. So, all things considered, I would take the advice from that article with a grain of salt. Yes, it is good advice, but there are more things to consider, as I have elaborated upon in the above paragraphs. ;-) That said, here's how I have organized things on this machine here... Filesystem Size Used Avail Use% Mounted on /dev/hda2 393M 179M 214M 46% / /dev/hda1 197M 38M 159M 20% /boot /dev/hda3 9.8G 2.5G 7.3G 26% /usr /dev/hda6 746M 33M 714M 5% /opt /dev/hda7 2.0G 359M 1.6G 18% /var /dev/hda8 298M 33M 266M 11% /usr/local /dev/hda9 79G 2.4G 77G 4% /home /dev/hda10 21G 3.2G 18G 16% /srv none 1014M 52K 1014M 1% /tmp The swap partition is "/dev/hda5", and it barely gets used. This is a 32-bit PCLinuxOS installation on a system with 2 GB of RAM, and as you can see, I have "/usr" pretty close up front, and "/home" still more to the rear, but this is a 120 GB hard disk and "/home" is by far the largest of the partitions. I have "/srv" last, but it only contains static data on this system - i.e. multimedia files which should be accessible to all user accounts - and it doesn't get used much. I also have "/tmp" on a tmpfs, so its contents live in RAM only, which is faster than any disk. Hope this helps. ;-) -- *Aragorn* (registered GNU/Linux user #223157) |