Date: Wed, 3 Jul 2013 13:09:23 -0700 From: Jeremy Chadwick <jdc@koitsu.org> To: Alexandr <shuriku@shurik.kiev.ua> Cc: "freebsd-fs@freebsd.org" <freebsd-fs@freebsd.org> Subject: Re: Whole disk ZFS or -a4k partition Message-ID: <20130703200923.GA70533@icarus.home.lan> In-Reply-To: <51D42416.8080604@shurik.kiev.ua> References: <51D3ED4F.5030102@shurik.kiev.ua> <8afaecbe0f764963b57fac7743f483bc@DBXPR07MB064.eurprd07.prod.outlook.com> <51D42416.8080604@shurik.kiev.ua>
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On Wed, Jul 03, 2013 at 04:16:06PM +0300, Alexandr wrote: > 03.07.2013 14:56, Ivailo Tanusheff =D0=BF=D0=B8=D1=88=D0=B5=D1=82: > > Hi, > > > > I can give you my point of view: > > > > Which zpool do you refer to? Still I would align both pools - on SSD = because you will have a boot code anyway.=20 > > What I would do on SSD is to use: > > gpart add -b 34 -s 94 -t freebsd-boot <ssd drive> > > > > The second thing I would get in mind Is the swap - I would not use a = ZFS for that, had a lot of issues with similar setup and taking into acco= unt that ZFS uses a lot of RAM you may become to situation when you want = to swap data to use RAM for ZFS functionality, related to the swap volume= on the ZFS subsystem, which is a deadlock scenario. > > So I would advise you to create swap partition on the SSD and use thi= s partition in the system. > > gpart add -t freebsd-swap -s 4G -l ssd-swap <ssd drive> > > gpart add -t freebsd-zfs -l ssd-zfs <ssd drive> > > > > This will solve you the alignment, swap issues and etc. > > > > About the second drive - there are two issues: may you need to replac= e the disk and will you need additional swap in some case. > > Just because future is unsure I would recommend to again use 4K align= , to create a similar SWAP partition and DO NOT use it on the system and = use gnop for the 4K sizing: > > gnop create -S 4096 /dev/gpt/disk0 > > zpool create zroot /dev/gpt/disk0.nop > > zpool export zroot > > gnop destroy /dev/gpt/disk0.nop > > zpool import zroot > > > > This way you will solve: > > - the 4K issues, if you have any; > > - the replacement issues, if you get a disk with smaller sector count= ; > > - in case you have some swap issues/needs, you will be able to issue = swapon /dev/gpt/... and temporary increasethe swap, but not using this al= l time you will not decrease performance of the system in normal days. > > > > Best regards, > > Ivailo Tanusheff > > > > > Thank you for your explain. I'll try it soon and post my results. One > thing - I can't use gpt-disks because off my laptop's bios (Lenovo > Thinkpad E530) cannot boot it, only mbr-style. You can use GPT with a BIOS that only supports MBR (in other words, you do not need UEFI to boot from GPT). FreeBSD's boot blocks are intelligent in this regard. I know because 1) I use this on my own systems that do not have UEFI, 2) tons of other people here do as well, and 3) because even Wikipedia states so. :-) --=20 | Jeremy Chadwick jdc@koitsu.org | | UNIX Systems Administrator http://jdc.koitsu.org/ | | Making life hard for others since 1977. PGP 4BD6C0CB |
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