Date: Sat, 22 Sep 2007 11:14:35 +0100 From: Gabriel Dragffy <gabe@dragffy.com> To: freebsd-questions@freebsd.org Subject: Re: Software RAID5 Message-ID: <96F69DFA-5ADF-41F6-B5B5-603F011D93CB@dragffy.com> In-Reply-To: <26ddd1750709211713o36dfabb5ua9f57747d75dc44@mail.gmail.com> References: <9F2B2568-9F37-4422-85F4-4740533A0DAD@dragffy.com> <26ddd1750709211713o36dfabb5ua9f57747d75dc44@mail.gmail.com>
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On 22 Sep 2007, at 01:13, Maxim Khitrov wrote: > > However, a simple solution to that is to get a 64+ MB USB flash drive > and put the kernel on that. Just use fdisk and bsdlabel to write the > boot blocks. As long as the kernel has all needed drivers and you > specify which root device to use (either via kernel configuration or > /etc/fstab), that should allow you to put everything else on the RAID > array. This is how I currently do full-disk encryption on my laptop > using GELI. Kernel is outside, everything else is encrypted, same idea > for RAID. > > I haven't ever done software RAID in FreeBSD, so can't help you with > the practical aspects of it. But I will say that technical or not, man > pages are still the best way to learn about these things. From what I > can see, RAID 5 is done through vinum, and GEOM offers RAID 3. Someone > else here may be able to tell you which one is better to use. > > It's also worth noting that with software, the performance of RAID 5 > is not going to be very good. I generally advise against software RAID > 5. If you want good performance and reliability using software RAID, > the best bet is RAID 10, but there the utilization is 50%. I think > that if you can afford another 500GB drive and performance is > important to you, a software RAID 10 using GEOM will perform much > better. It is also easier to recover, and you can lose two drives (not > any two, but still) without completely losing all the data. > Hi, thank you for your post. I read the following in the BSD handbook which lead me to believe I could have root on RADI5: <quote> There is another option as well, to have /boot/loader (Section 12.3.3) load the vinum kernel module early, before starting the kernel. This can be accomplished by putting the line: geom_vinum_load="YES" into the file /boot/loader.conf. </quote> That's here: http://www.freebsd.org/doc/en_US.ISO8859-1/books/ handbook/vinum-root.html I appreciate your post about using an alternative system to RAID 5. Many thanks Gabriel
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