Date: Thu, 9 Jul 2015 14:25:41 -0700 From: Charles Swiger <cswiger@mac.com> To: Paul Kraus <paul@kraus-haus.org> Cc: FreeBSD - <freebsd-questions@freebsd.org> Subject: Re: Gmirror/graid or hardware raid? Message-ID: <0B66BF03-53F6-4CDD-8530-6CFFA89D04EE@mac.com> In-Reply-To: <7F08761C-556E-4147-95DB-E84B4E5179A5@kraus-haus.org> References: <CA%2ByoEx-T5V3Rchxugke3%2BoUno6SwXHW1%2Bx466kWtb8VNYb%2BBbg@mail.gmail.com> <917A821C-02F8-4F96-88DA-071E3431C335@mac.com> <7F08761C-556E-4147-95DB-E84B4E5179A5@kraus-haus.org>
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On Jul 9, 2015, at 7:32 AM, Paul Kraus <paul@kraus-haus.org> wrote: > On Jul 8, 2015, at 17:21, Charles Swiger <cswiger@mac.com> wrote: [ ... ] >> Most of the PROD databases I know of working from local storage have heaps of >> RAID-1 mirrors, and sometimes larger volumes created as RAID-10 or RAID-50. >> Higher volume shops use dedicated SAN filers via redundant Fibre Channel mesh >> or similar for their database storage needs. > > Many years ago I had a client buy a couple racks FULL of trays of 36 GB SCSI drives (yes, it was that long ago) and partition them so that they only used the first 1 GB of each. This was purely for performance. They were running a relatively large Oracle database and lots of OLTP transactions. I seem to have memories of very expensive 18GB and 36GB 15K RPM Seagate Barracuda drives with SCA-2 connectors filling racks full of Sun E450s serving similar roles. :-) >>> I thought about zfs but I won't have lots of RAM avaliable >> >> ZFS wants to be run against bare metal. I've never seen anyone setup ZFS within >> a VM; it consumes far too much memory and it really wants to talk directly to the >> hardware for accurate error detection. > > ZFS runs fine in a VM and the notion that it _needs_ lots of RAM is mostly false. I have run a FBSD Guest with ZFS and only 1 GB RAM. No doubt FreeBSD + ZFS + low memory has improved from what it once was. But I also suspect that if you did something on the system which put a significant amount of memory pressure on that 1GB VM, it would handle such a load significantly better using UFS than using ZFS. That's a claim without #s, but someone with such a setup could run some benchmarks if they wanted to compare. [ ...The rest of your post was informative, and hopefully helpful to the OP as well-- but snipped since I don't have more specific things to say in reply.... ] Regards, -- -Chuck
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