Date: Sat, 26 May 2001 12:10:56 -0700 (PDT) From: Felix Hernandez <felix_hdez@yahoo.com> To: freebsd-questions@FreeBSD.ORG Subject: Slower tape drive when compression off Message-ID: <20010526191056.97775.qmail@web9502.mail.yahoo.com>
next in thread | raw e-mail | index | archive | help
Hi, I have a Quantum DLT8000 tape drive (40/80 GB), and I'm puzzled by the following fact: writing the tape in compressed mode (mt comp on) is faster (4 MB/s) than in uncompressed mode (mt comp off, 2 MB/s). I use tar (1.13) for my backups, and the tape is attached to an IBM Netfinity 7100 running FreeBSD 4.1. I have already tried a large and fixed blocksize (mt blocksize 10240, tar -b 20), but it didn't help. Do you know why this happens? How can I fix it? I don't want to use compression, since the data is already gzipped, and recompressing it wastes 5 GB. Regards, Felix Hernandez. --- /kernel: sa0 at ahc2 bus 0 target 5 lun 0 /kernel: sa0: <QUANTUM DLT8000 0119> Removable Sequential Access SCSI-2 device /kernel: sa0: 20.000MB/s transfers (10.000MHz, offset 8, 16bit) __________________________________________________ Do You Yahoo!? Yahoo! Auctions - buy the things you want at great prices http://auctions.yahoo.com/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20010526191056.97775.qmail>