Date: Wed, 28 Jan 2009 15:49:39 -0600 From: Dan Nelson <dnelson@allantgroup.com> To: Jaime <jaime@snowmoon.com> Cc: freebsd-questions@freebsd.org Subject: Re: Quantum tape drive Message-ID: <20090128214938.GE63837@dan.emsphone.com> In-Reply-To: <ae4324ed0901281238u4f1a1ddo400407115e6491f2@mail.gmail.com> References: <ae4324ed0901281136v80fd634t1cbed1f73170c2ef@mail.gmail.com> <20090128202349.GD63837@dan.emsphone.com> <ae4324ed0901281238u4f1a1ddo400407115e6491f2@mail.gmail.com>
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In the last episode (Jan 28), Jaime said: > On Wed, Jan 28, 2009 at 3:23 PM, Dan Nelson <dnelson@allantgroup.com> wrote: > > > > In the last episode (Jan 28), Jaime said: > >> /usr/bin/tar -cvpX /usr/local/etc/backups/skiplist-relative.txt -f /dev/sa0 -C / . > > > > If nothing else, I suggest bumping up your blocksize. The default for > > tar (10k) is pretty small for modern tape drives. Try -b 128 (for a 64k > > block size). Another optimization would be to put a buffering program > > in between tar and your tape drive to decouple disk reads from tape > > writes. misc/team, misc/buffer, and misc/cstream in ports are good for > > this. > > Thanks. Would this decrease the ability of other Unixes being able to > read the tape? For example, using pax (which can read tar archives) > or GNU's tar? It shouldn't. At worst you may have to specify a matching blocksize argument when reading. > Sadly, I forgot to mention something in my last message. Sorry. > > When reading from the tape using tar (bsdtar from FreeBSD 6.2 -- and, > yes, I'm preparing a cvsup as I write this :) ) the tape drive's Alarm > and Fault LEDs are lit up and then camcontrol devlist no longer shows > the tape drive. According to http://downloads.quantum.com/dlt_v4/DLT-V4_Product_Manual_81-81422-03_A01.pdf#page=67 , there is no alarm LED on a DLT-V4 drive, just Ready, Fault, Clean, and Media. If the Fault light is lit solid, it says that's an "Internal firmware error". If Fault and Clean are blinking slowly, you may have a bad tape or may need to put a cleaning tape in. > After I wrote to the tape via a quick boot into Knoppix, I found that > FreeBSD's tar command could list the files on the tape. So maybe that is > in the past now. Maybe not. I should have mentioned it earlier. Sorry. > > Any other thoughts before I try to OS update and the larger block size? -- Dan Nelson dnelson@allantgroup.com
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