Date: Mon, 30 Jul 2012 08:38:10 -0700 From: Waitman Gobble <gobble.wa@gmail.com> To: Wojciech Puchar <wojtek@wojtek.tensor.gdynia.pl> Cc: questions@freebsd.org, Vladimir Videscu <vladimir.videscu@gmail.com> Subject: Re: FreeBSD on SSD Message-ID: <CAFuo_fwABnGL5b9eiHMiZbBtLskhjb8ZpRWCQHDGdS8_Eig0Vw@mail.gmail.com> In-Reply-To: <alpine.BSF.2.00.1207282016110.9859@wojtek.tensor.gdynia.pl> References: <CAMxhPyt-gF228nX0DNrdsFVXKVx6YjZVa7obfov5vf%2BdtV71zw@mail.gmail.com> <alpine.BSF.2.00.1207281229260.6801@wojtek.tensor.gdynia.pl> <CAKB6gVgEyvVYaUvLkvE_AU-aViJxHAiLu6drcodLjOOBeNEYLg@mail.gmail.com> <CAMxhPysfghi-0ufy0OU0nonqha5mFeRacPVXM0MBDe6fqxmjUg@mail.gmail.com> <alpine.BSF.2.00.1207282016110.9859@wojtek.tensor.gdynia.pl>
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On Jul 28, 2012 11:42 AM, "Wojciech Puchar" <wojtek@wojtek.tensor.gdynia.pl> wrote: >> >> The read-cache idea is very sound, mainly because by using it this way Seagate would not have to create a special set of >> instructions for installing and using the HDD. > > > I don't think that this drive cache is smart enough to really cache needed things and not flush that cache with useless data too often. > > i personally would prefer that drive to show up as 8GB disk and 750 GB disk. > > It would be easy to fit most of /usr in 8GB with even large set of software installed. > > when out of space then use softlinks and move not very used things (eg. documentation, non-yours locales, examples, some linarly accessed big files etc.) to disk. > > >> My final question would be : >> >> Seeing as the HDD only has a SATA connector, this would mean that the SSD part already has a memory control device that regulates >> access to that sector, whether it is a plain read-cache or not. This would imply that FreeBSD could communicate with the HDD >> normally, through the SATA connector, just like any regular HDD. > > > indeed. > > Such a drive is a good idea, but complete lack of documentation (how it operate) is not. > > You have to guess how this SSD-cache works because it is not documented. > > the other thing is erasing data. You want to sell that drive and clear your data by > > dd if=/dev/zero of=/dev/disk bs=1m > > but does it clear SSD cache? i don't think so. Someone sophisticated enough would perform raw read of cache chips and get cached data, which can actually be the most important part (things you work on often). > > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to " freebsd-questions-unsubscribe@freebsd.org" I've been using one of these drives for a few months, bought it because of bargain price and it sounded cool.. but its true there is little documentation, there seems to be no way to look at the SSD cache. I've read on some ng that it takes 5 to 10 boots to "learn" which files are loaded at boot.. maybe true. Also have not performed any comparison tests but maybe it boots faster. ... its not like instant on though. :) Waitman Gobble San Jose California
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