Re: iostat - define Kilobits per transfer
I currently have an IDE drive that has the capacity to do 128KB/t and a SCSI drive 64KB/t. Are these stats in fact showing me that there is a limitation with the SCSI drive? Are my file transfering capaibilities less with the SCSI drive? I suppose what do I need to look for in the spcifications when choosing new drives so this does not happen again? FreeBSD's SCSI layer has a cap of 64k per transaction (apparently because ancient ISA adapters could not do more than 64k), and the ATA layer has a cap of 128k. You won't see a difference using regular disks. A 20MB/sec transfer rate comes out to ~300 64K transactions/sec, which most systems should be able to handle with no problems. so what exactly does KB per transaction mean? what happens if I am handling 300 concurrent users with 160Kbit encoded audio streams - could I in fact do this on this machine? or will I be limited by the 64KB/t issue? - Noah -- Dan Nelson [EMAIL PROTECTED] To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-questions in the body of the message
Re: iostat - define Kilobits per transfer
In the last episode (Jan 22), Noah Garrett Wallach said: can somebody give me a better understanding of what the iostat output is decribing in the KB/t column. It might be really simple but figured I';d ask, if in fact further clarification can be given. typhoon% iostat 1 tty da0 da1 acd0 tin tout KB/t tps MB/s KB/t tps MB/s KB/t tps MB/s us ni sy in 0 21 0.00 0 0.00 0.00 0 0.00 0.00 0 0.00 1 0 1 0 do drive specifications generally contain KB/t information or statistics? When there is disk activity, yes. Try running a couple du's or extract a couple ports, then run iostat in another window. I currently have an IDE drive that has the capacity to do 128KB/t and a SCSI drive 64KB/t. Are these stats in fact showing me that there is a limitation with the SCSI drive? Are my file transfering capaibilities less with the SCSI drive? I suppose what do I need to look for in the spcifications when choosing new drives so this does not happen again? FreeBSD's SCSI layer has a cap of 64k per transaction (apparently because ancient ISA adapters could not do more than 64k), and the ATA layer has a cap of 128k. You won't see a difference using regular disks. A 20MB/sec transfer rate comes out to ~300 64K transactions/sec, which most systems should be able to handle with no problems. -- Dan Nelson [EMAIL PROTECTED] To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-questions in the body of the message
Re: iostat - define Kilobits per transfer
I currently have an IDE drive that has the capacity to do 128KB/t and a SCSI drive 64KB/t. Are these stats in fact showing me that there is a limitation with the SCSI drive? Are my file transfering capaibilities less with the SCSI drive? I suppose what do I need to look for in the spcifications when choosing new drives so this does not happen again? FreeBSD's SCSI layer has a cap of 64k per transaction (apparently because ancient ISA adapters could not do more than 64k), and the ATA layer has a cap of 128k. You won't see a difference using regular disks. A 20MB/sec transfer rate comes out to ~300 64K transactions/sec, which most systems should be able to handle with no problems. so what exactly does KB per transaction mean? what happens if I am handling 300 concurrent users with 160Kbit encoded audio streams - could I in fact do this on this machine? or will I be limited by the 64KB/t issue? 300 x 160Kbit = approx. 46Mbit/sec. A new-ish SCSI drive should be able to easily pump out in excess of 200 Mbit/sec. Your bottleneck will be your ethernet adapter long before your local storage. Unless your app is designed very poorly. To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-questions in the body of the message
Re: iostat - define Kilobits per transfer
On Wed, 22 Jan 2003, Dax Eckenberg wrote: so what exactly does KB per transaction mean? what happens if I am handling 300 concurrent users with 160Kbit encoded audio streams - could I in fact do this on this machine? or will I be limited by the 64KB/t issue? 300 x 160Kbit = approx. 46Mbit/sec. A new-ish SCSI drive should be able to easily pump out in excess of 200 Mbit/sec. Your bottleneck will be your ethernet adapter long before your local storage. Unless your app is designed very poorly. okay things are getting clearer over here. what exactly does KB per transaction mean? I dont understand what this describes? - Noah To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-questions in the body of the message
Re: iostat - define Kilobits per transfer
On Thursday 23 January 2003 5:40 am, Noah Garrett Wallach wrote: On Wed, 22 Jan 2003, Dax Eckenberg wrote: so what exactly does KB per transaction mean? what happens if I am handling 300 concurrent users with 160Kbit encoded audio streams - could I in fact do this on this machine? or will I be limited by the 64KB/t issue? 300 x 160Kbit = approx. 46Mbit/sec. A new-ish SCSI drive should be able to easily pump out in excess of 200 Mbit/sec. Your bottleneck will be your ethernet adapter long before your local storage. Unless your app is designed very poorly. okay things are getting clearer over here. what exactly does KB per transaction mean? I dont understand what this describes? - Noah To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-questions in the body of the message my guess :- iostat -Iw 60 -t da ad0 KB/tXfrs MB 8.42710.58 so over the period, 71 transfers occurred totalling 0.58MB for an average KB/t of (0.58*1024) / /71 = 8.37 KB/t but maybe the actual avg transfer size is recorded and summarized giving that slight variation?. Try a longer period and see, or read the code.. (the math starts around line 600) To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-questions in the body of the message
