From Bugzilla Helper: User-Agent: Mozilla/4.7 [de] (WinNT; I) Description of problem: DEll PowerEdge with 4 XEON 1.4GHz, 4GB System hangs. I can't do any ping, telnet, console switch. keybord and Monitor freeze Version-Release number of selected component (if applicable): How reproducible: Sometimes Steps to Reproduce: Waiting 4 or 5 hours without any heavy work on it Actual Results: The system hangs Expected Results: It had to run! Additional info: On kernel-smp-2.4.18-3 and kernel-smp-2.4.18-4 we have no Problems. The problem occurs with kernel-bigmem-2.4.18-17.7.x and kernel-smp-2.4.18-17.7.x . I found lines like this in dmesg: ------------------- megaraid: channel[2] is raid. scsi3 : LSI Logic MegaRAID 1.72 254 commands 15 targs 5 chans 7 luns blk: queue f71ee218, I/O limit 4095Mb (mask 0xffffffff) scsi3: scanning virtual channel 0 for logical drives. Vendor: MegaRAID Model: LD 0 RAID1 138G Rev: 1.72 Type: Direct-Access ANSI SCSI revision: 02 blk: queue f6fc8e18, I/O limit 4095Mb (mask 0xffffffff) scsi3: scanning virtual channel 1 for logical drives. scsi3: scanning virtual channel 2 for logical drives. ------------------- Is this normal (blk:...) ?
yes that's normal do you have a tg3 network card ? (eg broadcom 57xx ?)
may be Broadcom BCM 95701 Gigabit (i am not able to look at the system at the moment)
It is a Bradcomm BCM5700
can you for now try changing "tg3" to "bcm5700" in /etc/modules.conf ?
Ethernet controller: BROADCOM Corporation NetXtreme BCM5700 Gigabit Ethernet (rev 14) Subsystem: Dell Computer Corporation NetXtreme 1000BaseTX
I changed "tg3" to "bcm5700" in /etc/modules.conf an the System runs up to now 15 hours. When the system doesnt hang until Monday I think that was the solution. BTW: 4GB and 4 XEON, is it better to use the bigmem or the smp kernel? We use Informix Dynamic Server Version 9.30.UC2 on that system. Is it recommendable to enable Hyperthreading?
bigmem vs smp: 4Gb is the exact border case, so the answer is "depends". That needs explaining: The PCI bus needs a "window" in the address range to operate, and that window needs to be below 4Gb (32 bit). On PC's with less than 4Gb ram that is obviously no problem since there is plenty of unused space. If you have 4Gb or more, there wouldn't be any unused space, so what happens is that the chipset forces a hole. Some chipsets will "move" the memory that was in the hole to above the 4Gb range, others just make the ram disappear. We're talking about in the order of 300Mb of ram normally. The SMP kernel (by design) will not use RAM over 4Gb, while the bigmem kernel can, at the cost of overall performance (supporting this is more expensive in several places, since 64 bit pointers have to be used for some things). Our installer will automatically select the bigmem kernel if it finds ram > 4Gb, but I can also see it by hand if I see the first about 20 lines of dmesg (eg the so called "e820" table). If the potential extra 300Mb is worth it? Depends a bit on your workload but usually yes (because it serves as a cache for the disks, and disks are REALLY slow compared to ram). As for hyperthreading: for some workloads hyperthreading is a win, for others it is a loss. In my experience for databases it tends to be a slight loss, but I have no experience with Informix in specific.
[root@rinnen_lin root]# uptime 7:53am up 3 days, 14:37, 1 user, load average: 0.04, 0.01, 0.00 I think changing the driver was the solution. Thanks a lot! Michael Mehlhorn PS: BTW where can I mark this Request as "resolved"?