partitioning revisited
Hi, I have just build a machine, and am ready to start putting the stable on it. This is the first time I have built one from scratch, and it has made me think in detail about what I am doing as I put it all together. Now as I am newish to Linux I thought you might indulge me her. On two other boxes I have here I have potato running fine, but as I think about it there may be a better set-up. To help me get to the enlightened approach could I pick the panel brains on the following? 1: I recently read that logical partitions were better than primary because of the size limits on the directories. I didn't quit understand this. On this laptop I have 4 primary partitions, with the 4th holding 4 logical. Is this unwise? Should I just have one big logical partition? 2: In my other machines I have 128 Mb memory, so I have had a 128 Mb swap file. In my new machine I have taken advantage of the low price and put 512 Mb in it. This set me thinking, and I cannot reconcile the following I have been told or read; a: With 512 Mb ram you don't need a swap file b: You must have a swap file 2x ram c: Over 128 Mb ram you must have a swap file of there same size d: A swap file cannot be over 128 Mb e: A swap file cannot be over 256 Mb f: A swap file cannot be over 512 Mb g: Swap files must be in multiple of 128 Mb h: Swap files are an irrelevance on modern machines My questions are not from a lack of research, rather I have found out too much which is contradictory. I would like some guidance in sorting the what from the chaff here Keith -- +--+ | Keith O'Connell | That which does not kill | | Maidstone, Kent (UK) | us, usually still hurts. | | [EMAIL PROTECTED] | That's just life, I'm afraid | +--+
partitioning revisited
Hi, I have just build a machine, and am ready to start putting the stable on it. This is the first time I have built one from scratch, and it has made me think in detail about what I am doing as I put it all together. Now as I am newish to Linux I thought you might indulge me her. On two other boxes I have here I have potato running fine, but as I think about it there may be a better set-up. To help me get to the enlightened approach could I pick the panel brains on the following? 1: I recently read that logical partitions were better than primary because of the size limits on the directories. I didn't quit understand this. On this laptop I have 4 primary partitions, with the 4th holding 4 logical. Is this unwise? Should I just have one big logical partition? 2: In my other machines I have 128 Mb memory, so I have had a 128 Mb swap file. In my new machine I have taken advantage of the low price and put 512 Mb in it. This set me thinking, and I cannot reconcile the following I have been told or read; a: With 512 Mb ram you don't need a swap file b: You must have a swap file 2x ram c: Over 128 Mb ram you must have a swap file of there same size d: A swap file cannot be over 128 Mb e: A swap file cannot be over 256 Mb f: A swap file cannot be over 512 Mb g: Swap files must be in multiple of 128 Mb h: Swap files are an irrelevance on modern machines My questions are not from a lack of research, rather I have found out too much which is contradictory. I would like some guidance in sorting the what from the chaff here Keith -- +--+ | Keith O'Connell | That which does not kill | | Maidstone, Kent (UK) | us, usually still hurts. | | [EMAIL PROTECTED] | That's just life, I'm afraid | +--+
Re: partitioning revisited
High, On Thu, 9 Aug 2001, Keith O'Connell wrote: Hi, I have just build a machine, and am ready to start putting the stable on it. This is the first time I have built one from scratch, and it has made me think in detail about what I am doing as I put it all together. Now as I am newish to Linux I thought you might indulge me her. On two other boxes I have here I have potato running fine, but as I think about it there may be a better set-up. To help me get to the enlightened approach could I pick the panel brains on the following? 1: I recently read that logical partitions were better than primary because of the size limits on the directories. I didn't quit understand this. On this laptop I have 4 primary partitions, with the 4th holding 4 logical. Is this unwise? Should I just have one big logical partition? dunno about this one 2: In my other machines I have 128 Mb memory, so I have had a 128 Mb swap file. In my new machine I have taken advantage of the low price and put 512 Mb in it. This set me thinking, and I cannot reconcile the following I have been told or read; These are just rules of thumb. I think it is the following: a: With 512 Mb ram you don't need a swap file only if you are not a heavy user b: You must have a swap file 2x ram true, until c: comes true c: Over 128 Mb ram you must have a swap file of there same size true d: A swap file cannot be over 128 Mb afaik, it can be e: A swap file cannot be over 256 Mb afaik, it can be f: A swap file cannot be over 512 Mb afaik, it can be g: Swap files must be in multiple of 128 Mb I think it is wise that it is a multiple of your real memory. But, 1x ram and 2x ram is a multiply (so it is not necesary to have a 128MB multiply) h: Swap files are an irrelevance on modern machines perhaps. BTW: Mb means Megabit, is should be MB. Hope this enlighten things a bit. Greetz, Sebastiaan My questions are not from a lack of research, rather I have found out too much which is contradictory. I would like some guidance in sorting the what from the chaff here Keith -- +--+ | Keith O'Connell | That which does not kill | | Maidstone, Kent (UK) | us, usually still hurts. | | [EMAIL PROTECTED] | That's just life, I'm afraid | +--+ -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED]
Re: partitioning revisited
My $0.02's worth re. swap: Suppose you are consistently using 256MB of swap on your fairly up-to-date machine. That means you definitely need to buy and install 256MB RAM, which is dirt cheap today. Therefore, I think on a modern machine, the swap space should be equal to the minimum amount of memory you will be adding next. Monitor swap usage, and as soon as it looks like you're consistently swapping, go out and buy more dirt-cheap RAM. On older machines with small amounts of memory you used to be swapping for dear life with a multi-user multi-tasking OS like Linux, which is probably the origin of the swap=3xRAM rule. Best regards, George Karaolides 8, Costakis Pantelides St., tel: +35 79 68 08 86 Strovolos, email: [EMAIL PROTECTED] Nicosia CY 2057, web: www.karaolides.com Republic of Cyprus
Re: partitioning revisited
on Thu, Aug 09, 2001 at 09:00:03AM +0100, Keith O'Connell ([EMAIL PROTECTED]) wrote: 1: I recently read that logical partitions were better than primary because of the size limits on the directories. I didn't quit understand this. On this laptop I have 4 primary partitions, with the 4th holding 4 logical. Is this unwise? Should I just have one big logical partition? There's no benefit I'm aware of. Some OSs may prefer only on primary partition, or suffer other limitations, but most such issues are historical only. 2: In my other machines I have 128 Mb memory, so I have had a 128 Mb swap file. In my new machine I have taken advantage of the low price and put 512 Mb in it. This set me thinking, and I cannot reconcile the following I have been told or read; I've got three general rules of thumb with swap: - Swapping sucks. - Running out of memory sucks more. - Repartitioning sucks most. There's also a lot of obsolete data floating around about GNU/Linux in general. a: With 512 Mb ram you don't need a swap file If you're not swapping, this is true. b: You must have a swap file 2x ram Not true. But a good rule of thumb. c: Over 128 Mb ram you must have a swap file of there same size We'll bet back to this. d: A swap file cannot be over 128 Mb e: A swap file cannot be over 256 Mb f: A swap file cannot be over 512 Mb From mkswap(8): The maximum useful size of a swap area now depends on the architecture. It is roughly 2GiB on i386, PPC, m68k, ARM, 1GiB on sparc, 512MiB on mips, 128GiB on alpha and 3TiB on sparc64. g: Swap files must be in multiple of 128 Mb h: Swap files are an irrelevance on modern machines Myths. My questions are not from a lack of research, rather I have found out too much which is contradictory. I would like some guidance in sorting the what from the chaff here Simple truth on swap: swapping is a kludge. The benefit is your program (or worse: system) doesn't fall over because it runs out of (expensive, fast) physical RAM. The penalty is you sacrifice some disk space, and a shitload of time, swapping data. Swapping works reasonably well on a tuned system because there are programs which aren't called very often -- they can page out to disk, and stay there until they're needed, at which point something else is swapped and the first program gets some CPU cycles. When this happens, you get the illusion of much more physical memory than you've got. When it happens a lot, your disks grind endlessly and your maching is made of February molassas. The old 2x RAM rule of thumb is still a pretty good one. Everyone's got more memory these days (and it's damned cheap for current architectures), but programs and systems are getting bigger. I actually prefer to give my systems about 2x the maximum possible memory as swap, even if this means they've got 3-4x memory. Reason being that it's far easier to add memory (drop the system, pop the case, squeeze the sticks in) than it is to repartition (back up, verify, back up again, verify again, repartition, reformat, restore, verify). As for sizing swap, I've got partitions variously of 132 MB, 128 MB, and 486 MB, on various systems. Other considerations include distribution of swap. On a SCSI system, span spindles, if at all possible, preferably with swap on each physical disk. IDE offers fewer I/O benefits unless you have multiple controllers, but spanning may help minimize head movement. I'd generally discourage use of swap files unless absolutely necessary. Realize too the downsides are relatively bearable: too little swap, and you can't run really big (or lots of) apps. Too much (and too little memory), and you're going to be spending a lot of time exercising it. Bad disk allocation -- you'll lose a touch of speed. The world is unlikely to end as a consequence. -- Karsten M. Self kmself@ix.netcom.com http://kmself.home.netcom.com/ What part of Gestalt don't you understand? There is no K5 cabal http://gestalt-system.sourceforge.net/ http://www.kuro5hin.org Free Dmitry! Boycott Adobe! Repeal the DMCA!http://www.freesklyarov.org Geek for Hirehttp://kmself.home.netcom.com/resume.html pgpGum8o0hufF.pgp Description: PGP signature
Re: partitioning revisited
Hi Keith, I will try and help as best I can with some of these questions, and more! First, I would like to recommend that you read the partitioning how-to at http://www.linuxdoc.org/HOWTO/mini/Partition/partition-4.html On Thu, Aug 09, 2001 at 09:00:03AM +0100, Keith O'Connell wrote: Hi, I have just build a machine, and am ready to start putting the stable on it. This is the first time I have built one from scratch, and it has made me think in detail about what I am doing as I put it all together. Now as I am newish to Linux I thought you might indulge me her. On two other boxes I have here I have potato running fine, but as I think about it there may be a better set-up. To help me get to the enlightened approach could I pick the panel brains on the following? 1: I recently read that logical partitions were better than primary because of the size limits on the directories. I didn't quit understand this. On this laptop I have 4 primary partitions, with the 4th holding 4 logical. Is this unwise? Should I just have one big logical partition? I, like Sebastiaan, am not sure about the limit of directory sizes for primary paritions as opposed to logical's contained withing an extended partition. As for the layout of your partitions you should split them up corresponding to the filesystems that they will contain. When everything is put on one big partition data can start to get a little spread out and disorganized. And lets say something strange happens and your system is logging it. The logs could exhaust the available space, likely hanging your system if the root filesystem is lumped together with all filesystems. And if you have filesystem corruption, one directory hierarchy can affect others. Splitting up partitions helps limit systematic problems if corruption occurs on a directory. Also, security can be a concern with one big parition. It's best not not to put the root filesystem on the same filesystem as user filesystems, as this may allow 'set user id'(SUID) programs to have more of a potential to gain access to restricted areas. You should consider mounting filesystems with the 'nosuid' option(specified in /etc/fstab) anywhere that you think local or remote users might be up to no good. For instance, if you are running an anonymous ftp server you might want to give it it's own partition and mount that filesytem as 'nosuid'. I got most of the above info from reading a book callied 'Maximum Linux Security'. 2: In my other machines I have 128 Mb memory, so I have had a 128 Mb swap file. In my new machine I have taken advantage of the low price and put 512 Mb in it. This set me thinking, and I cannot reconcile the following I have been told or read; a: With 512 Mb ram you don't need a swap file b: You must have a swap file 2x ram c: Over 128 Mb ram you must have a swap file of there same size d: A swap file cannot be over 128 Mb e: A swap file cannot be over 256 Mb f: A swap file cannot be over 512 Mb g: Swap files must be in multiple of 128 Mb h: Swap files are an irrelevance on modern machines The amount of space you want to give for a swap partition depends on a few system specific factors, imo. It depends on how much memory you have, how large of programs you run and how many. I see that Karsten seemed to have answered that how big a swap partition can be depends on the machine architecture, and this same info is also contained the the partitioning how-to at the url I gave. Where you place it can depend upon a few things too. If you are not hardly ever giong to be making use of swap, I suggest putting towards the rear of the drive. If you think you are going to be using all your ram and hitting the swap occasionaly and/or on a regular basis then I recommend putting it towards the front of the drive, where access by the drive heads occurs pretty quickly, or next to a partition where you believe a lot of drive activity occurs and the drives heads are spending a lot of their time already, such as /usr. My questions are not from a lack of research, rather I have found out too much which is contradictory. I would like some guidance in sorting the what from the chaff here Keith -- +--+ | Keith O'Connell | That which does not kill | | Maidstone, Kent (UK) | us, usually still hurts. | | [EMAIL PROTECTED] | That's just life, I'm afraid | +--+ -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED] All in all, I hope this and others who have responded have helped, Jimmy Richards Q: What did the instructor at the school for Kamikazi pilots say to his students?
Re: partitioning revisited
Oh, A couple things I wanted to include that I forgot. Just thought I would let you know that I have 512 MB's of ram and felt that I wouldn't be using swap very much, so I made my swap partition 256 MB. And, in case it's of any help, here is some info about my layout. I just made an extended partition and all my logical partitions are within it. I didn't use a primary myself. Disk /dev/hdc: 255 heads, 63 sectors, 2495 cylinders Units = cylinders of 16065 * 512 bytes Device BootStart EndBlocks Id System /dev/hdc1 1 2495 200410565 Extended /dev/hdc5 * 1 3 24034+ 83 Linux /dev/hdc6 412 72261 83 Linux /dev/hdc713 2035 16249716 83 Linux /dev/hdc8 2036 2243 1670728+ 83 Linux /dev/hdc9 2244 2402 1277136 83 Linux /dev/hdc10 2403 2433248976 82 Linux swap /dev/hdc11 2434 2487433723+ 83 Linux /dev/hdc12 2488 2495 64228+ 83 Linux FilesystemSize Used Avail Use% Mounted on /dev/hdc6 68M 43M 22M 66% / /dev/hdc5 23M 3.5M 19M 16% /boot /dev/hdc7 15G 5.1G 10G 34% /usr /dev/hdc8 1.6G 1.1G 547M 66% /var /dev/hdc9 1.2G 37M 1.1G 4% /home /dev/hdc11410M 181M 225M 45% /opt /dev/hdc12 61M 4.1M 56M 7% /tmp HTH, Jim Richards
Re: partitioning revisited
On Thu, Aug 09, 2001 at 03:02:57AM -0700, Karsten M. Self wrote: SNIP - Swapping sucks. - Running out of memory sucks more. - Repartitioning sucks most. There's also a lot of obsolete data floating around about GNU/Linux in general. I have a question that seems appropriate here. In the newer 2.4.x kernels there's an issue with swap, correct? I have noticed this with the last 2.4.6 kernel I built, and the 2.4.5 before that. Some nasty javascript would chew up a whack of memory, and then some swap would be used. The process would be killed eventually, but the swap was _not_ freed. I had to manually swapoff and swapon to free it, and this was only marginally preferable to rebooting. SNIP b: You must have a swap file 2x ram Not true. But a good rule of thumb. SNIP The old 2x RAM rule of thumb is still a pretty good one. Everyone's got more memory these days (and it's damned cheap for current architectures), but programs and systems are getting bigger. I actually prefer to give my systems about 2x the maximum possible memory as swap, even if this means they've got 3-4x memory. Reason being that it's far easier to add memory (drop the system, pop the case, squeeze the sticks in) than it is to repartition (back up, verify, back up again, verify again, repartition, reformat, restore, verify). As for sizing swap, I've got partitions variously of 132 MB, 128 MB, and 486 MB, on various systems. Again, how does this relate to the above swap feature in the 2.4.x kernels that are AFAIK not yet fixed? If this has been fixed, please let me know as I have been checking the changelogs at kernel.org, and seen no mention of swap issues being addressed in the last little while. TIA, -- Mike Pfleger There's seventy brilliant people on earth. Where are they hiding? Yashar -Cabaret Voltaire (off of 2x45)
Re: partitioning revisited
On approximately Thu, Aug 09, 2001 at 01:22:57PM -0700, Mike Pfleger wrote: that are AFAIK not yet fixed? If this has been fixed, please let me know as I have been checking the changelogs at kernel.org, and seen no mention of swap issues being addressed in the last little while. Check out the latest ac kernel and the latest linus kernel also. Linus has been working on vm balancing as a top priority recently and the latest ac has a patch to fix the swap=2*ram thing. Josh
Re: partitioning revisited
On Thu, Aug 09, 2001 at 03:45:24PM -0500, Josh McKinney wrote: SNIP Check out the latest ac kernel and the latest linus kernel also. Linus has been working on vm balancing as a top priority recently and the latest ac has a patch to fix the swap=2*ram thing. Josh That's cool; Ill go and have a look once this backup is merrily doing its own thing. Thanks a bunch. Cheers, -- Mike Pfleger There's seventy brilliant people on earth. Where are they hiding? Yashar -Cabaret Voltaire (off of 2x45)
