Date: Sun, 4 Feb 2007 13:53:14 -0800 (PST) From: Aloha Guy <alohaguy123@yahoo.com> To: Scott Long <scottl@samsco.org> Cc: questions@freebsd.org, current@freebsd.org Subject: Re: swap file vs swap partition Message-ID: <393982.95591.qm@web53614.mail.yahoo.com>
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Thanks for the input. You do have good points. The only issue with swap p= artitions is that it seems like you need to increase it everytime you incre= ase the physical memory. Is there a swap partition size limit that pretty = much will handle anything and setting a number larger than that will really= not offer anything?=0A=0AJohn=0A=0A----- Original Message ----=0AFrom: Sco= tt Long <scottl@samsco.org>=0ATo: Aloha Guy <alohaguy123@yahoo.com>=0ACc: q= uestions@freebsd.org; current@freebsd.org=0ASent: Sunday, February 4, 2007 = 12:16:37 PM=0ASubject: Re: swap file vs swap partition=0A=0A=0AAloha Guy wr= ote:=0A> Greetings everyone:=0A> =0A> I am planning to build a few new boxe= s which will run -RELEASE and -CURRENT and I have a question about the swap= file. In the past, I had always used a swap partition of 256MB since I or= iginally had 128MB system memory in the 1990's but my system has been upgra= ded to 2GB and it seems the swap file would have more flexibility as I can = just change the size of the swapfile if I needed to. My question is is ther= e any difference in performance between a swap file versus a swap partition= and can one run a system with a swap file instead of a swap partition?=0A= =0AYes. A swap file requires a pass through the filesystem code in order= =0Ato figure out where each block is.=0A=0A> Also, searching has not gotten= me very far but are there any drawbacks to a swap file instead of a swap p= artition? I read somewhere that a few people seem to think that a swap fil= e can't handle kernel crash dumps?=0A=0AThat's correct, it cannot.=0A=0A> S= houldn't it be the same as both of them occupy disk space and as long as th= e swap file is large enough, wouldn't it work?=0A=0AThe crashdump code is w= ritten to assume that the dump space is=0Acompletely contiguous, something = that is not at all guaranteed by=0Aa swap file. While it would certainly b= e possible to modify it=0Ato make a pass through the filesystem like above,= the intention=0Aof the crashdump code is also to be as simple as possible = and to=0Adepend on as few kernel services as possible. When the system has= =0Acrashed, who knows what can be trusted anymore, right? Also, filesystem= =0Acorruption is a frequent cause of crashes; why risk that dumping to=0Aa = swapfile might encounter corruption and trash your entire filesystem.=0A=0A= Scott=0A=0A=0A =0A_________________________________________________________= ___________________________=0AGet your own web address. =0AHave a HUGE yea= r through Yahoo! Small Business.=0Ahttp://smallbusiness.yahoo.com/domains/?= p=3DBESTDEAL
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