Date: Sun, 3 Sep 2000 14:19:30 -0500 (CDT) From: Chris Dillon <cdillon@wolves.k12.mo.us> To: Christian Weisgerber <naddy@mips.inka.de> Cc: freebsd-scsi@FreeBSD.ORG Subject: Re: Keeping a DLT4000 streaming? Message-ID: <Pine.BSF.4.21.0009031400140.90484-100000@mail.wolves.k12.mo.us> In-Reply-To: <8oth09$u2b$1@ganerc.mips.inka.de>
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On 3 Sep 2000, Christian Weisgerber wrote: > If any of you guys have a DLT4000 (or faster) tape drive, and > manage to keep it streaming properly _with compression enabled_, > I'd like to know your setup. Keeping a DLT4000 streaming would be a lot harder than keeping a DDS2/3 drive streaming, but I keep my DDS drive streaming (with no H/W compression, I have to use gzip instead) by using several large 'team' (ports/misc/team) buffers. I currently use five 8MB buffers. A buffer only empties when it is full, so that way only 8MB streamable chunks make it to the drive, even if the disks can't keep all of the buffers full. You might want 32MB at a time or more for a DLT drive that is doing its own compression. I believe I had to modify the team code to get even an 8MB buffer. One disadvantage to using something like team is that the buffers exist entirely in system RAM, so you'll need plenty of free RAM if you want large buffers. -- Chris Dillon - cdillon@wolves.k12.mo.us - cdillon@inter-linc.net FreeBSD: The fastest and most stable server OS on the planet. For Intel x86 and Alpha architectures. ( http://www.freebsd.org ) To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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