Alvin Oga, 2003-Mar-31 17:03 -0800: > > hi ya Greetings > On Mon, 31 Mar 2003, Jeff wrote: > > > I've seen a reference to two regarding the location of a partition on > > the HDD being faster than other parts of the HDD. I've been trying to > > get a definitive answer on this and it's still not clear to me. > > > the disk spins at the same rotational rpm ... its the "same" speed
Now that I sit and think about that, I see it now. > what you can do, is to add more data ( sectors ) on a given tract > say 64 sectors per track vs 256 sectors on the outer tracks > ( doing so screws up your pll and other analog signals > ( but is worth it if you want to maximize capacity > > - whether reading 64* 512bytes/sector or 256 * 512byte/sector > is better/worst is up to the app ... and how data is written I'll have to ponder this for awhile. Don't quite get it yet. > - less moving of the heads is generally faster as it takes too long > to move the head relative to just reading data > > > - track 0 ( first partitions ) is ALWAYS on the outside of the disk Thanks for clearing that up for me. > - example pic of partition layout on the disk > > http://www.linux-1u.net/Partition/ Fantastic web site! I'll be spending some time there. Pictures are good! > - careful selection of bytes per sector also helps > 512 byte /sector vso 1024 or 2048 bytes/sector > ( bytes per inode ) > > - but all that is lots-o-headaches > and you'd need to write data to disk to take those extra > tweeks into account for maximum benefit Uhuh. > - calculate ... 5400rpm vs 7200rpm vs 10,000rpm vs 15,000rpm > - defaults is 512 bytes/sector > - defaults is 64 sectors per track > - defaults is "n" number of physical heads ( number of platters ) > > - for each revolution of disk ... you get xxxKB/sec of disk > transfer > > - ignore all those marketing numbers of ata-66, ata-100, > ata-133 > > - for ide disks -- 1st round no-brainer speed comparason/optimization > > - fiddle with some of the hdparm options and check its effects > > - hdparm -tT /dev/hda > > - hdparm -d 1 -u 1 -m 16 -c 3 /dev/hda > ( make sure your disk supports the options first ) > > - turn on dma ( -d 1 ) > - turn on intr ( -u 1 ) > - turn on multicount ( -m 16 ) > - turn on 32bit io ( -c 3 ) > > - set the proper ATA speed ( -X69 for ata-100 ) > > http://www.linux-1u.net/Disks/hdparm.txt I've spent time learning how to use hdparm and have been able to boost performance for my drives most of the time. I haven't gotten anything better than around 20Mbps, but that's better than 4. > > - dont forget to account for 2MB disk cache and 8MB disk cache > > - simpler to just add a 2nd spindle ( /dev/hdc ) and be able > to read data 2x faster than with one disk ( /dev/hda ) > - initial writing of data and parity will be slightly slower > > - other ways to improve your system > > http://www.linux-1u.net/Tuning/ Thanks Alvin. I've got some studying to do. :-) jc -- Jeff Coppock Systems Engineer Diggin' Debian Admin and User -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
