Performance degration of moving FFS hdd from a slow to a fast pc.
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 I have a question about FFS filesystem. According to a paper about the design of UFS filesystem[1], if you create the FFS filesystem on a slow cpu and then move it to a fast cpu with a fast controller, theh the FFS wont perform efficient. This is justified because when the UFS is created having in mind the speed of the system, in order to create the cyllinder group summary information with optimal rotationally blocks [see page 7 of the paper]. If somebody takes the hdd of the slow pc and put it on a much faster pc, then it is reported that the throughput will drop significantly because of lost disk revolutions. I would like to know if this is true. Can I move my hdd of my old slow pc [intel 486] to a pentium III 600Mhz machine without performance penatly, or its better to re-create the filesystem? Thank you very much... References: [1] http://citeseer.nj.nec.com/mckusick84fast.html - --- We are being monitored..but there is a solution... Use PGP for signing and encrypting emails Download my public key at http://www.us.pgp.net -BEGIN PGP SIGNATURE- Version: GnuPG v1.2.0 (FreeBSD) iD8DBQE93M3XGe/V3CxAyHoRAtCKAJsFEPJAEgYOzE8NkszHO5jUBETrnwCfTC+V vLYTHw2fXGYPIwfuzA3TitM= =/4V2 -END PGP SIGNATURE- To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-questions in the body of the message
Re: Performance degration of moving FFS hdd from a slow to a fast pc.
In the last episode (Nov 21), BigBrother (BigB3) said: I have a question about FFS filesystem. According to a paper about the design of UFS filesystem[1], if you create the FFS filesystem on a slow cpu and then move it to a fast cpu with a fast controller, theh the FFS wont perform efficient. This is justified because when the UFS is created having in mind the speed of the system, in order to create the cyllinder group summary information with optimal rotationally blocks [see page 7 of the paper]. If somebody takes the hdd of the slow pc and put it on a much faster pc, then it is reported that the throughput will drop significantly because of lost disk revolutions. I would like to know if this is true. Can I move my hdd of my old slow pc [intel 486] to a pentium III 600Mhz machine without performance penatly, or its better to re-create the filesystem? Those optimizations were long since removed from the FFS code. The old C/H/S style of disk layout hasn't been used in 10 years (which means that FFS's logical cylinder groups do not correspond with the physical sylinders on the hard drive anymore), and CPUs are so fast that there is no need to compensate for a slow CPU anymore. You can put the disk in a faster PC and it will work optimally. -- Dan Nelson [EMAIL PROTECTED] To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-questions in the body of the message
