victorvittorivonwiktow at interfree.it
Thu Jul 28 00:07:43 GMT 2005
[Technicians' or hackers' suggestions seem like music to me. Thanks. I
am compelled on this shit system, owing to the need of managing some
commercial stuff. I hate it. Please forgive me for using it].
I have compared some features among different current tape drive
standards. It seems DLT and LTO Ultrium 2 cartridges are more expensive
then DAT 72 and VXA 2 ones. I have not found yet a criterion useful to
choose the most reliable standard. Any suggestion could be useful. I'll
need either to dump or to tar.
Please CC me. Thanks once more.
---- Original Message ----
From: "Glenn Dawson" <glenn at antimatter.net>
To: "Chuck Swiger" <cswiger at mac.com>; ".VWV."
<victorvittorivonwiktow at interfree.it> Cc:
<freebsd-questions at freebsd.org> Sent: Wednesday, 27 July, 2005 05:19
Subject: Re: certance DAT
> At 08:17 PM 7/26/2005, Chuck Swiger wrote:
> ...so it's not exactly super-zippy, either. Hmm, is it just me, or
> are the following numbers significantly low for a RAID-1 of two 10K
> RPM U320 SCSI disks...?
>> 512 # sectorsize
>> 73274490880 # mediasize in bytes (68G)
>> 143114240 # mediasize in sectors
>> 8908 # Cylinders according to firmware.
>> 255 # Heads according to firmware.
>> 63 # Sectors according to firmware.
>> Seek times:
>> Full stroke: 250 iter in 1.824059 sec = 7.296 msec
>> Half stroke: 250 iter in 1.805398 sec = 7.222 msec
>> Quarter stroke: 500 iter in 4.254147 sec = 8.508 msec
>> Short forward: 400 iter in 2.821081 sec = 7.053 msec
>> Short backward: 400 iter in 2.860203 sec = 7.151 msec
>> Seq outer: 2048 iter in 8.821875 sec = 4.308 msec
>> Seq inner: 2048 iter in 9.006505 sec = 4.398 msec
>> Transfer rates:
>> outside: 102400 kbytes in 9.242111 sec = 11080
>> kbytes/sec middle: 102400 kbytes in 9.230325 sec =
>> 11094 kbytes/sec inside: 102400 kbytes in 10.779231
>> sec = 9500 kbytes/sec
>> [ This is running RELENG_5_4... ]
> I would have expected the transfer rates to be about twice what
> they're listed as here. Though I don't know how you measured them.
> If you want to see something interesting, create a ufs1 file system
> on the same raid 1 using FreeBSD 4.x. Then mount it in 5.x and do
> your test for transfer rates. Compare that to either ufs1 or ufs2 on
> the same raid 1 as created by 5.4.
> The results are very interesting.
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