Experinces with Swap size & AHA-2940

Yavuz Darendelioglu (bioyavuz@rorqual.cc.metu.edu.tr)
Tue, 7 May 1996 11:04:02 +0400 (MEDT)

On Mon, 6 May 1996, Atakan Gurkan wrote:

> Date: Mon, 6 May 1996 13:08:45 +0400
> From: Atakan Gurkan <agurkan@newton.physics.metu.edu.tr>
> To: Multiple recipients of list <linux@bilkent.edu.tr>
> Subject: Re: ext2 problems on fast-wide SCSI-2 (fwd)
> Selamlar,
> Ya assagida bir seyler var. Sanki daha once listede yazilanlarla
> celisiyor gibi geldi. Bi' baksak.

The problems that Mr.Bradford faces may not be due to swap size. Following
is the partition list of my Linux box (wasp.bio.metu.edu.tr):

Disk /dev/sda: 255 heads, 63 sectors, 268 cylinders
Units = cylinders of 16065 * 512 bytes

Device Boot Begin Start End Blocks Id System
/dev/sda1 * 1 1 128 1028128+ 6 DOS 16-bit >=32M
/dev/sda2 129 129 138 80325 82 Linux swap
/dev/sda3 * 139 139 268 1044225 83 Linux native

Device Boot Begin Start End Blocks Id System
/dev/sdb1 * 1 1 96 771088+ 83 Linux native
/dev/sdb2 97 97 173 618502+ 83 Linux native
/dev/sdb3 174 174 250 618502+ 83 Linux native
/dev/sdb4 251 251 261 88357+ 82 Linux swap

Device Boot Begin Start End Blocks Id System
/dev/sdc1 1 1 13 104391 6 DOS 16-bit >=32M
/dev/sdc2 14 14 16 24097+ 82 Linux swap
/dev/sdc3 17 17 48 257040 83 Linux native
/dev/sdc4 49 49 260 1702890 83 Linux native

/dev/sda is 2GB SCSI-2 (Conner 2105S)
/dev/sdb is 2GB SCSI-2 (Quantum)
/dev/sdc is 2GB SCSI-2 (Conner 2105S)

These disks are attached on an ADAPTEC AHA-2940 PCI-SCSI controller. The
system is AT&T, P-100, Globalyst 630 with a memory of 64MB RAM.
Therefore, I may reserve a total of ~120 Swap size BUT NOT more than this.
However, with current conditions I mostly not needed that much of Swap
space. Therefore, I enabled only the first swap partition which is around

I tested Swap spaces of both (/dev/sda2 + /dev/sdc2) and (/dev/sdb4
+ /dev/sda3). Apparently, I had no problems. On the other hand, I never
tried three of these Swap spaces together. Which is, to my knowledge,
not worth to try as far as I know the max. limit is ~120MB.

Outcomes of my experiences:

1. You may set multiple Swap partitions on multiple disks.
2. Your first partition MUST BE on the first disk. (Regardless of its size)
3. If you have big memory on system, you really don't need bigger Swap.
(Remember, If have larger memory, your system swaps lesser)
4. I cannot say about the limit for number of Swap Partitions. The figure 8
seems me logical. But, it is meaningless to use this many number of partitions.
5. Also, It is worth to note that creating a Swap of 100MB, let's say for a
system with 16 MB RAM is meaningless and this may cause problems.
6. I faced frequent disk errors when I removed one of the 32MB RAM out of
system for using on another system. The reason for this wasp the
architecture of my system, which requires identical RAM Chips on the both
slots of the first bank.
7. If I were to set up this system from begining I would buy Future
Domain's PCI-SCSI adapter instead AHA-2940 due to SCSI-BIOS version
problems. I initially had to fight with many problems with
AHA(wasp.bio.metu.edu.tr). However, seting up Linux with Future Domain
was as easy as seting on an IDE adapter (behcet.gazi.tip.edu.tr).


Yavuz Darendelioglu,
Dept of Biology, METU
Network & Syst. Admin.

> ---------- Forwarded message ----------
> Date: Sat, 4 May 1996 08:31:38 -0700 (PDT)
> From: Mishelle Bradford <bradford@cs.unr.edu>
> >
> > It's a P150 (Tyan Tempest II) with 64MB RAM, a DPT PM2124W Fast/Wide
> > SCSI-2 controller, a Fujitsu M2934QA 4GB F/W SCSI-2 drive that's been
> > partitioned to have sda1 as a 300-odd MB root partition and sda4 as a
> > 32MB swap partition, and a 3c595 Ethercard.
> >
> Swap partitions can only be a max of 16MB in size, last I heard, and there
> can be a total of 8 swap partitions.
> The wide scsi might be problematic too... I don't think Adaptec 2940 wide
> is supported, but maybe the DPT PM2124W is.
> >
> > I'm open to any suggestions---I kind of went out on a limb suggesting
> > a Linux box rather than a SS20, and I must admit I'm feeling sort of
> > foolish right now. Fortunately, I'm not under terrifically heavy
> > deadline pressure to get this deployed.
> Don't know how many of the errors you are getting are due to the swap
> space size being too large, but hopefully most or all will be resolved
> by reducing it and adding another to make a total of 32MB. Also, did
> you set the swap space type to 82 in fdisk?
> I wish you luck... I believe you made a good choice of systems.
> Shell

Yavuz Darendelioglu
Ankara / TURKEY