Date: Sat, 18 Mar 2017 00:06:52 +1100 (EST) From: Ian Smith <smithi@nimnet.asn.au> To: Matthias Apitz <guru@unixarea.de> Cc: Warren Block <wblock@wonkity.com>, freebsd-questions@freebsd.org Subject: Re: bootable ext. USB SSD for backup Message-ID: <20170317230124.V31244@sola.nimnet.asn.au> In-Reply-To: <mailman.83.1489752002.47481.freebsd-questions@freebsd.org> References: <mailman.83.1489752002.47481.freebsd-questions@freebsd.org>
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In freebsd-questions Digest, Vol 667, Issue 6, Message: 5 On Thu, 16 Mar 2017 20:46:12 +0100 Matthias Apitz <guru@unixarea.de> wrote: > I have acquired a small and flat USB 3.0 external disk (must be SSD for > the size of the case): > > Mar 16 19:36:54 c720-r314251 kernel: da0: <TOSHIBA External USB 3.0 5438> Fixed Direct Access SPC-4 SCSI device > Mar 16 19:36:54 c720-r314251 kernel: da0: Serial Number 20170114010787F Hi Matthias, Can you give an URL to specs for this model? I had a quick hunt and was amazed how fast prices have come down for big SSDs, so I'm interested. > Mar 16 19:36:54 c720-r314251 kernel: da0: 40.000MB/s transfers That's on a USB 2.0 port, right? For USB 3.0 it would say 400MB/s .. > Mar 16 19:36:54 c720-r314251 kernel: da0: 953869MB (1953525164 512 byte sectors) > Mar 16 19:36:54 c720-r314251 kernel: da0: quirks=0x2<NO_6_BYTE> > > Ofc it has not the promised 1 TB volume, just only 953869 MB, i.e. only > 1 Marketing-TB; Yeah, it's been that way for a decade or two .. even smartctl reports in 10^x units, e.g. this is the '64GB' SSD that came with my Lenovo X200: root@x200:~ # smartctl -i /dev/ada0 | egrep 'Model|Capacity|Sector|Rotation|ATA' Device Model: SAMSUNG MMCRE64G8MPP-0VA User Capacity: 64,023,257,088 bytes [64.0 GB] Sector Size: 512 bytes logical/physical Rotation Rate: Solid State Device ATA Version is: ATA/ATAPI-7 T13/1532D revision 1 root@x200:~ # echo 'scale=3; 64023257088 / 1024^3' | bc 59.626 If you have smartmontools installed, I'd be interested in seeing a 'smartctl -Ai /dev/da0' for this device? Offlist if you prefer. > I'm thinking in re-partitioning the disk (which is actual only one big > NTFS slice) with gpart(8), install even a kernel into a small FS at the > beginning and keep the rest as a big UFS for backups. Having it bootable > with a system could be handy if one has to rescue a system and restore > the last dunp. Even 20GB would be 'small' on this; it could double as a spare system. If it were me I'd more likely add, say, 3 x ~310GiB partitions, but I'd be dumping a larger number of smaller FS, keeping several generations. cheers, Ian PS: there's been some fun - and some rather tedious - nonsense written on this thread, but if I were the judge, first prize must go to Warren: > (The memory units used above are actually gwibblybytes (GwB), 1012 > 7.9-bit bytes per kwibblybyte (KwB), 1011 KwB per mibblybyte (MwB), and > 1010 MwB per gwibblybyte, or about fourteen thousandths short of a > dwibblyliter (DwL).)
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