Date: Fri, 19 Aug 2005 12:48:19 +0200 From: =?ISO-8859-1?Q?Bj=F6rn_K=F6nig?= <bkoenig@cs.tu-berlin.de> To: Vasim Valejev <vasim@human-capital.ru> Cc: freebsd-amd64@freebsd.org Subject: Re: Slow PCI-X controller perfomance (adaptec 2130SLP) Message-ID: <4305B8F3.7080904@cs.tu-berlin.de> In-Reply-To: <00d601c5a88e$1cb8c260$2107a8c0@vasimwork> References: <00d601c5a88e$1cb8c260$2107a8c0@vasimwork>
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Vasim Valejev wrote: > I've tried to set up FreeBSD-current on Dual opteron box with Adaptec 2130SLP > PCI-X RAID controller (256MB memory). My tests did show that maximum transfer > rate from controller to OS was about 132MB/s. That is very strange since PCI-X > maximum speed should be about 1GB/s. Why the controller was so slow? [...] 132 MB/s is a very good transfer rate. Keep in mind that 1 GB/s is the theoretical limit of the PCI-X bus which means that single devices do not necessarily accomplish this transfer rate. As far as I can remember the maximum read transfer rate of a RAID 5 is n - 1, i.e. if one drive has a maximum transfer rate of 80 MB/s then three of them in a RAID 5 array can't have more than 160 MB/s. Björn
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