Date: Sat, 15 Mar 2008 08:09:28 -0500 From: David Wassman <DWassman@davismonk.com> To: <wojtek@wojtek.tensor.gdynia.pl> Cc: freebsd-questions@freebsd.org Subject: Re: Sync or Soft Updates or gjournal Message-ID: <4EFE19E52F4F844D997F24D759C4A23B03875669@etg2.etg.local>
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Wojciech, =20 Thanks for the response. I like gmirror and actually use it for two production machines but in this case, I think I still prefer to use the hardware RAID5 (for online expansion and rebuilds) and I always prefer to use SAS/SCSI if given a choice. Anyways, the hardware is already purchased. =20 So gjournal will slow it down. It is hard to believe all the hype of journalled filesystems is all about not having to fsck on boot. (Yes I know it is fsck not fschk (other post). Been working with M$ too much). =20 Does anyone know why Michael Lucas would say "up to 80GB" for soft updates? I start FreeBSD with Absolute BSD and Scary Daemons and has always found his advice solid and reliable. I hate to go against it here and be wrong. Especially, when this is a large project with the fate of FreeBSD being used in the environment here at stake.=20 =20 =20 David Wassman, MCP Net+ IT Network Administrator Davis, Monk & Company (800) 344-5034 (352) 372-6300 (352) 375-1583 FAX The information contained in this electronic message is legally privileged and confidential under applicable law, and is intended only for the use of the individual or entity named above. If you are not the intended recipient, you are hereby notified that any dissemination, copying or disclosure of this communication is strictly prohibited. If you have received this communication in error, please notify Davis, Monk & Company (352) 372-6300 and delete this communication immediately without reading it, making any copies of it or distributing it. =20 >=20 > My question is with this setup (Have not assembled or installed yet), > for a fileserver running Samba to share in mixed environment, what would > be better, sync, soft updates or gjournal. From my understanding, sync =20 first - for the same amount of money, use cheaper and larger SATA disks, no special controller and RAID1 (gmirror), not RAID5. while RAID1 "wastes" half space, with large IDE drives you still get more=20 space, while SATA drives are slightly slower, you still get FASTER system=20 on writes because RAID5 is bad for this, and on reads. gain on not using RAID5 will outperform slower drives. =20 > is the most secure as far as data integrity but suffers from > performance. Soft Updates is a mix between the two but from reading =20 soft updates isn't the mix of two - it's much better. you actually get=20 sync integrity with almost async performance, but with larger CPU=20 usage, which - with modern CPUs - is minimal anyway. =20 just use them :) =20 gjournal will actually slow things down, for avoiding fsck on boot. =20 properly configured freebsd doesn't crash every day so spending an hour=20 (at most) on fsck doesn't make a problem. =20
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