Date: Wed, 03 Sep 2003 21:22:59 +0300 From: Petri Helenius <pete@he.iki.fi> To: Max Clark <max.clark@media.net> Cc: freebsd-performance@freebsd.org Subject: Re: 20TB Storage System (fsck????) Message-ID: <3F563183.3080103@he.iki.fi> In-Reply-To: <ILENIMHFIPIBHJLCDEHKOECFDDAA.max.clark@media.net> References: <ILENIMHFIPIBHJLCDEHKOECFDDAA.max.clark@media.net>
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Max Clark wrote: >Ohh, that's an interesting snag. I was under the impression that 5.x w/ PAE >could address more than 4GB of Ram. > > It does. However as long as a pointer is 32 bits, your address space for a process is maxed out at 4G which translates to about 2.5G user after kernel and other things have taken their toll. >If fsck requires 700K for each 1GB of Disk, we are talking about 7GB of Ram >for 10TB of disk. Is this correct? Will PAE not function correctly to give >me 8GB of Ram? To check 10TB of disk? > PAE functions correctly but does not provide for 7G address space. >Is there anyway to bypass this requirement and split fsck into smaller >chunks? Being able to fsck my disk is kinda important. > > Yes, you do that by splitting up the filesystem to smaller filesystems. Kind of obvious? >I have zero experience with either itanium or opteron. What is the current >status of support for these processors in FreeBSD? What would the preferred >CPU be? Will there be PCI cards that I would not be able to use in either of >these systems? > > I´m personally biased towards the Opteron, but that´s more based on that it makes more sense than their technical merits so far (because neither has too much). Both CPU´s should work fine with 5.2 according to the TODO list. Meanwhile I suggest you play with the number of inodes on the 10TB filesystem and see how that affects the memory usage. Petehelp
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