Date: Sun, 08 May 2005 14:28:02 +0200 From: willem jan withagen <wjw@digiware.nl> To: Steven Hartland <killing@multiplay.co.uk> Cc: freebsd-current@freebsd.org Subject: Re: Very low disk performance Highpoint 1820a Message-ID: <427E05D2.2060706@digiware.nl> In-Reply-To: <002b01c553be$93a5b790$b3db87d4@multiplay.co.uk> References: <069901c54bfd$2967ba40$7f06000a@int.mediasurface.com> <427D5AA0.1080609@withagen.nl> <002b01c553be$93a5b790$b3db87d4@multiplay.co.uk>
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Steven Hartland wrote: > If that where the case it would have been it wouldn't have been > 46Mb/s it would have been 543Mb/s, just tested it for you :P >>> I've just finished putting together a new server box spec: >>> Dual AMD 244, 2GB ram, 5 * Seagate SATA 400GB on a >>> Highpoint 1820a RAID 5 array. >> >> >>> 5.4-STABLE Highpoint 1820a RAID 5 ( 5 disk ) >>> 655360000 bytes transferred in 13.348032 secs (49097875 bytes/sec) >> >> You're only transfering 640M in 2GB of RAM, big chance that you're >> testing memory/buffercode-speed in stead of testing diskspeed. Still I would argue that if you do not use a write size larger than what you have as real memory, that buffering in real memory is going to play a role.... Other than that I find 50Mb/s is IMHO reasonable high value for a RAID5 in writting. But it would require substantial more organised testing. DD is nothing more than a very crude indication of what to expect in real life. --WjW
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