Re: 1 swap vs. 2 swap partitions
On Tue, Jan 26, 1999 at 09:02:48AM +0100, Helge Hafting wrote: > Any IDE setup with drives on different cables will improve > when you split swap over several drives. this because such drives > can be accessed simultaneously. > > Don't bother spreading swap across drives on the *same* IDE cable, > they can't be accessed simultaneously and will improve nothing. Two drives > on the same cable is very much like a single bigger drive - it is > the least useful setup for any purpose. But it's better than just one swap. You still get the advantage of lower seek times, hopefully. Also, on my last motherboard Linux did not seem to support DMA bus mastering on the second controllre, only on the first. That's worth consideration too. Hamish -- Hamish Moffatt VK3TYD [EMAIL PROTECTED], [EMAIL PROTECTED] Latest Debian packages at ftp://ftp.rising.com.au/pub/hamish. PGP#EFA6B9D5 CCs of replies from mailing lists are welcome. http://hamish.home.ml.org
Re: 1 swap vs. 2 swap partitions
> On Sat, Jan 23, 1999 at 11:06:18AM -0600, Andrew Ivanov wrote: > > > Hi. > > I recently added a new HD to my system, and I have a chance to put an > > additional swap on it. > > The question is: is there any gain in speed of accessing swap memory if > > instead of one big swap on one disk I have 2/more small ones on separate > > disks? > > Yes, there is, at least with SCSI or SCSI/EIDE. > > If you just have EIDE and the drives are reasonably recent, > I'd give it a try, too. Any IDE setup with drives on different cables will improve when you split swap over several drives. this because such drives can be accessed simultaneously. Don't bother spreading swap across drives on the *same* IDE cable, they can't be accessed simultaneously and will improve nothing. Two drives on the same cable is very much like a single bigger drive - it is the least useful setup for any purpose. Helge Hafting
Re: 1 swap vs. 2 swap partitions
On Sat, Jan 23, 1999 at 11:06:18AM -0600, Andrew Ivanov wrote: > Hi. > I recently added a new HD to my system, and I have a chance to put an > additional swap on it. > The question is: is there any gain in speed of accessing swap memory if > instead of one big swap on one disk I have 2/more small ones on separate > disks? Yes, there is, at least with SCSI or SCSI/EIDE. If you just have EIDE and the drives are reasonably recent, I'd give it a try, too. -- thomas..powered.by.debian/linux. irc.:.#meeting.points, #frust.ger
Re: 1 swap vs. 2 swap partitions
Hi Alexander, > > Doesn't this ignore the fact that having two heads working back and > > forth is faster than just one? Part of the reason people do raid arrays, > > even at the lower levels, because they get all the heads working at the same > > time and it lowers access time. I'd think the same would apply to swap. > > for this you'd need raid support for swap. I am not sure if swap could be on a > raid ... however, I am pretty sure that swap has no build in raid support. Actually, there IS some kind of RAID support built into the swapping code. If you activate 2 swap partitions with equal priority, all swapping will get distributed equally to those partitions - that might give some performance increase, of course! (add parameter pri=xx to /etc/fstab swap entry.) HTH. Tino.
Re: 1 swap vs. 2 swap partitions
hi Ship's Log, Lt. Steve Lamb, Stardate 230199.1723: > Doesn't this ignore the fact that having two heads working back and > forth is faster than just one? Part of the reason people do raid arrays, > even at the lower levels, because they get all the heads working at the same > time and it lowers access time. I'd think the same would apply to swap. for this you'd need raid support for swap. I am not sure if swap could be on a raid ... however, I am pretty sure that swap has no build in raid support. Greetings -- Alexander N. Benner - Christen im Internet - http://www.christen.net/ pgp : E7BCBEBD 53 5F 48 0A 0D 3E 4A 38 A8 11 B1 AF BE 08 C8 B0 MegaHAL: In John, Jesus is said to be Zerg.
Re: 1 swap vs. 2 swap partitions
On Sat, Jan 23, 1999 at 12:14:34PM -0500, Shaleh wrote: > In general, no. Swap is not really a big concern unless you are memory Doesn't this ignore the fact that having two heads working back and forth is faster than just one? Part of the reason people do raid arrays, even at the lower levels, because they get all the heads working at the same time and it lowers access time. I'd think the same would apply to swap. -- Steve C. Lamb | Opinions expressed by me are not my http://www.calweb.com/~morpheus| employer's. They hired me for my ICQ: 5107343 | skills and labor, not my opinions! ---+- pgpH6V7r2d9r5.pgp Description: PGP signature
RE: 1 swap vs. 2 swap partitions
On 23-Jan-99 Andrew Ivanov wrote: > Hi. > I recently added a new HD to my system, and I have a chance to put an > additional swap on it. > The question is: is there any gain in speed of accessing swap memory if > instead of one big swap on one disk I have 2/more small ones on separate > disks? > TIA, > Andrew In general, no. Swap is not really a big concern unless you are memory starved. However if do a lot of disk accessing, placing the swap on a separate device DOES help. otherwise the seek heads have to constantly pan back and forth from data to swap.
1 swap vs. 2 swap partitions
Hi. I recently added a new HD to my system, and I have a chance to put an additional swap on it. The question is: is there any gain in speed of accessing swap memory if instead of one big swap on one disk I have 2/more small ones on separate disks? TIA, Andrew Never include a comment that will help | Andrew Ivanov someone else understand your code. | [EMAIL PROTECTED] If they understand it, they don't | ICQ: 12402354 need you. |
