Date: Sun, 17 Jan 2010 14:26:42 +0100 From: "Ronald Klop" <ronald-freebsd8@klop.yi.org> To: "Dan Naumov" <dan.naumov@gmail.com>, "Rick Macklem" <rmacklem@uoguelph.ca>, freebsd-questions@freebsd.org, freebsd-fs@freebsd.org Subject: Re: (SOLVED) Re: installing FreeBSD 8 on SSDs and UFS2 - partition alignment, block sizes, what does one need to know? Message-ID: <op.u6oiatop8527sy@212-123-145-58.ip.telfort.nl> In-Reply-To: <cf9b1ee01001150857j7df80a65ma07f3b8e25f5b10@mail.gmail.com> References: <cf9b1ee01001150857j7df80a65ma07f3b8e25f5b10@mail.gmail.com>
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On Fri, 15 Jan 2010 17:57:03 +0100, Dan Naumov <dan.naumov@gmail.com> =20 wrote: > On Fri, Jan 15, 2010 at 6:38 PM, Rick Macklem <rmacklem@uoguelph.ca> =20 > wrote: >> >> >> On Tue, 12 Jan 2010, Dan Naumov wrote: >> >>> For my upcoming storage system, the OS install is going to be on a >>> 80gb Intel SSD disk and for various reasons, I am now pretty convince= d >>> to stick with UFS2 for the root partition (the actual data pool will >>> be ZFS using traditional SATA disks). I am probably going to use GPT >>> partitioning and have the SSD host the swap, boot, root and a few >>> other partitions. What do I need to know in regards to partition >>> alignment and filesystem block sizes to get the best performance out >>> of the Intel SSDs? >>> >> I can't help with your question, but I thought I'd mention that there >> was a recent post (on freebsd-current, I think?) w.r.t. using an SSD >> for the ZFS log file. It suggested that that helped with ZFS perf., so >> you might want to look for the message. >> >> rick > > I have managed to figure out the essential things to know by know, I > just wish there was a single, easy to grasp webpage or HOWTO > describing and whys and hows so I wouldn't have had had to spend the > entire day googling things to get a proper grasp on the issue :) Maybe you can copy-paste your e-mail in a wiki somewhere. And your wish =20 has come true for other peoples. Ronald. > To (perhaps a bit too much) simplify things, if you are using an SSD > with FreeeBSD, you: > > 1) Should use GPT > > 2) Should create the freebsd-boot partition as normal (to ensure > compatibility with some funky BIOSes) > > 3) All additional partitions should be aligned, meaning that their > boundaries should be dividable by 1024kb (that's 2048 "logical blocks" > in gpart). Ie, having created your freeebsd-boot, your next partition > should start at block 2048 and the partition size should be dividable > by 2048 blocks. This applies to ALL further partitions added to the > disk, so you WILL end up having some empty space between them, but a > few MBs worth of space will be lost at most. > > P.S: My oversimplification was in that MOST SSDs will be just fine > with a 512 kb / 1024 block alignment. However, _ALL_ SSDs will be fine > with 1024 kb / 2048 block alignment. > > > - Sincerely, > Dan Naumov > _______________________________________________ > freebsd-fs@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-fs > To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org"
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