Date: Mon, 11 Aug 2003 12:01:22 -0600 From: "Justin T. Gibbs" <gibbs@scsiguy.com> To: Don Bowman <don@sandvine.com>, "'Kenneth D. Merry'" <ken@kdm.org> Cc: "'aic7xxx@freebsd.org'" <aic7xxx@freebsd.org> Subject: RE: Ongoing U320 AIC7902 Seagate ST318453LW issues, SCB timed out Message-ID: <2442282704.1060624882@aslan.btc.adaptec.com> In-Reply-To: <FE045D4D9F7AED4CBFF1B3B813C853370274221F@mail.sandvine.com> References: <FE045D4D9F7AED4CBFF1B3B813C853370274221F@mail.sandvine.com>
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> So i've reconfirmed, the drive supports a max of 64 tags. > under load I see the max go down to 252, how can that make > sense? under severe load it may go lower, to e.g. 33. The actual number of transactions these drives support depends heavily on load. For reads, I believe that you can have much more than 64 commands outstanding to this drive. Once you start to fill the write buffer, the number of commands the drive can hold drops to 32 or 33 depending on the firmware rev. It seems that command resources are managed dynamically and that deferrred writes hold on to those resources while they are draining to the media. -- Justin
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