Date: Thu, 13 Feb 2020 20:08:27 -0800 From: David Christensen <dpchrist@holgerdanske.com> To: freebsd-questions@freebsd.org Subject: Re: some questions about disk partitioning and filesystems and booting Message-ID: <091dd3af-7b99-267f-7d04-541b6d651926@holgerdanske.com> In-Reply-To: <20200213150229.GC14144@bastion.zyxst.net> References: <20200213150229.GC14144@bastion.zyxst.net>
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On 2020-02-13 07:02, tech-lists wrote: > Hi, > > [1] > When a new (12.x) amd64 system is installed, the partition defaults to > MBR. I > normally use this as it's the default. I don't run mixed-OS systems; > they are > all freebsd. But I understand that GPT is newer or "better"? > > If GPT is "better" then why is it not the default? > > My use case is always ufs for the OS and zfs for data. Would it be > "better" to > use GPT when installing a system? I put my operating system installations on single, small 2.5" SATA SSD's and I put 2.5" SATA trayless disk bays in my computers. This both facilitates imaging and allows me to mix and match as required. For FreeBSD, I use ZFS throughout. Not all of my computers support booting from GPT, so I use MBR for system drives. The default FreeBSD installer wants to use the entire disk, so I hacked the memstick installer and/or choose the following in the installer: - 1 MiB alignment for everything - 14 GiB slice - 2 GiB boot partition, copies=2 - 2 GiB swap partition, mirrored - 10 GiB root partition, copies=2 The most obvious downside is that MBR does not support labels. So, the FreeBSD boot system uses device node names. This means I have to ensure that the system drive is always ada0 -- during install, whenever I move the drive to another machine, and whenever I add or remove drives or controllers. If the drive comes up as the wrong device node, I move SATA cables around. > [2] > The bsdinstaller defaults to 4GB swap. Isn't this insufficient on a 32GB > system? Doesn't swap need to be 2x RAM on a fast disk? > > The next install I do I'm thinking of making 2x 32GB swap partitions. These > being on the same SSD as the base OS. Would you consider this to be > suboptimal, and if so, why? In the past, I tried running systems without swap. They crashed. My current preference is to have plenty of RAM and a nominal swap partition. One possibility might be to install with a small swap partition now and put a large dummy partition at the end in case you need more swap later. Then again, if your workload does require a lot of swap, you could add a dedicated swap device and disable the swap partition on the system drive. David
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