Re: fiber
Simon Tennant wrote: Catalin Ciocoiu wrote: Lenght of a BNC ethernet trunc can be 320m ! Width a good cable you can force the limit at 350m. Most 10mbs hubs have a bnc connextor width 180/320m switch ! Be careful with this solution - it relies on the 2 locations being on the same power grid. If not you may run into some grounding problems. Exist BNC terminator width GND connector This can solve the grounding problem. S. -- Simon Tennant, Web Team, Linuxcare, Inc. 415.577.6719 tel, 415.701.7457 fax pgp id: 05F76248FF62442C4D0010C09851C0746410974D Linuxcare. Support for the revolution.
Re: 2500 Linux workstation !
Russell Coker wrote: On Thu, 27 Jul 2000, Catalin Ciocoiu wrote: In a slashdot articol somebody lace a interesing question What is the best solution for a network width 2500 Linux WorkStation ? I proposed a diskless workstation sollution becose is very robust sollution. Is it a good sollution What filesystem can be used for file sharing ?? Is NFS ok ??? What kind of authentification can be used in this network ? I waiting your answares !! One problem with diskless workstations is the issue of what happend when they all reboot simultaneously (EG power failure). I suggest that you setup a diskless workstation that is fully configured (X, xdm, etc), reboot it and track the amount of data transfer that is required. I guess that it might be about 30M of data access on disk. Multiply that by 2500 and that's 75G of data transfer, it would be 2 hours of network transfer on 100baseT if you didn't have timeouts and retransmits. Of course with that load you would have heaps of timeouts and it would take much longer... Whell On this network can be more than 1 fileserver and the traffic can be splited on more network segment. One file server for 50-100 station can be ok ! The file server for 100 station is on the same net segment width the station. This can reduce subtantial net traffic over segments. The /usr dir can be the same. And most files on the slash can be hard link for the same inod( eg: /bin/ls ). The good thing about diskless booting is that all machines will access mostly the same files if you have it configured correctly. The boot space of a diskless machine should fit into cache on the server (so disk bandwidth shouldn't be an issue). If you have a server with 10 * 100baseT network interfaces or 1 * 1G interface (the most that the bus bandwidth of typical PC servers can handle) then it could possibly handle 800 PCs for booting in a reasonable amount of time (5-10 minutes). So if you had 4 such machines for running the boot process (IE the root file system) and another set of machines for /home (which is much harder because the data is more important) then it could be workable. One thing I have been thinking of doing (an item on my almost infinitely long todo list) is to hack a kernel to log the details of file access (file name and the operation (read/write/etc) and the amount of data to klog and then have a modified klogd write this data to a file which is outside this logging (can't have it logging it's own accesses ;). Then I could boot the machine (NB would need a extra-large klogd buffer to capture file access before klogd had been loaded) and find out how much disk access really happens at boot. -- My current location - X marks the spot. X X X -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED]
Re: fiber
Lenght of a BNC ethernet trunc can be 320m ! Width a good cable you can force the limit at 350m. Most 10mbs hubs have a bnc connextor width 180/320m switch ! You can get a link width 10Mb/s bandwidth. Other sollution is two etherent segment linked width a ethernet repeater. Other 10Mbs sollution is thin etnernet that support 500m/per segment. Russell Coker wrote: On Tue, 25 Jul 2000, Allen Ahoffman wrote: Can someone comment here on reasons to use fiber for network cable now instead of old style standard cat5 cable? I see lots of fiber equipment out there but 100mbps is 100mbps right? Is fiber economical when you get into over 100mbps situations? thanks. Fiber currently allows gigabit speeds. But there are some companies offering gigabit over Cat5 cable (but the quality of the cable would have to be significantly greater than most Cat5 implementations...). For 100M Cat5 is what you want. Installing a 100baseT network is really easy, especially as most people don't need a dedicated 100M to their desktop so you just run two cables to each group of desks in an office (one spare just in case) and have a desktop switch. -- My current location - X marks the spot. X X X -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED] -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
2500 Linux workstation !
In a slashdot articol somebody lace a interesing question What is the best solution for a network width 2500 Linux WorkStation ? I proposed a diskless workstation sollution becose is very robust sollution. Is it a good sollution What filesystem can be used for file sharing ?? Is NFS ok ??? What kind of authentification can be used in this network ? I waiting your answares !!
Re: fiber
Lenght of a BNC ethernet trunc can be 320m ! Width a good cable you can force the limit at 350m. Most 10mbs hubs have a bnc connextor width 180/320m switch ! You can get a link width 10Mb/s bandwidth. Other sollution is two etherent segment linked width a ethernet repeater. Other 10Mbs sollution is thin etnernet that support 500m/per segment. Russell Coker wrote: On Tue, 25 Jul 2000, Allen Ahoffman wrote: Can someone comment here on reasons to use fiber for network cable now instead of old style standard cat5 cable? I see lots of fiber equipment out there but 100mbps is 100mbps right? Is fiber economical when you get into over 100mbps situations? thanks. Fiber currently allows gigabit speeds. But there are some companies offering gigabit over Cat5 cable (but the quality of the cable would have to be significantly greater than most Cat5 implementations...). For 100M Cat5 is what you want. Installing a 100baseT network is really easy, especially as most people don't need a dedicated 100M to their desktop so you just run two cables to each group of desks in an office (one spare just in case) and have a desktop switch. -- My current location - X marks the spot. X X X -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED]
Re: NIC install problem
Run the follow test: cat /proc/pci | less Try to find your ethernet entry. If you not find ethernet information in /proc/pci your card have a problem... You can compile a monolitic kernel width ne2k-pci support. If your ethernet card work the kernel detect automaticaly your interface. Áts Attila wrote: Thank you for the answers regarding docs. I've got an install problem. I want to install my Ethernet card (NE2000 compatible PCI produced by KTI Networks). I start modconf, choose net, choose ne2k-pci, get a message The ne2k-pci module is not currently installed. I choose Install, get a message Parameter documentation for this module is unavailable and installation fails. What can be the problem and the solution? Best regards Attila -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED] -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
Re: NIC install problem
Run the follow test: cat /proc/pci | less Try to find your ethernet entry. If you not find ethernet information in /proc/pci your card have a problem... You can compile a monolitic kernel width ne2k-pci support. If your ethernet card work the kernel detect automaticaly your interface. Áts Attila wrote: Thank you for the answers regarding docs. I've got an install problem. I want to install my Ethernet card (NE2000 compatible PCI produced by KTI Networks). I start modconf, choose net, choose ne2k-pci, get a message The ne2k-pci module is not currently installed. I choose Install, get a message Parameter documentation for this module is unavailable and installation fails. What can be the problem and the solution? Best regards Attila -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED]
Re: resource limits?
Fork bomb not work..
But
while (1) malloc(1000);
You must limit memoryuse
Dariush Pietrzak wrote:
root$ man ulimit
Isn't this a bash shell level thing?
% ulimit
ulimit: Command not found.
So what happens when you have users using tcsh? ulimit is not available in
limit [-h] [resource [maximum-use]]
tcsh. Can't users also change their ulimit settings? What about preventing
they can only lower limits enforced by admin.
fork bombs such?
this is limit's output at one of our university servers:
limit
cputime unlimited
filesizeunlimited
datasizeunlimited
stacksize 8192 kbytes
coredumpsize100 kbytes
memoryuse unlimited
descriptors 256
memorylockedunlimited
maxproc 256
openfiles 256
fork bomb won't do much with limited maxproc etc..
under Debian GNU/Linux you set it in /etc/login.defs:
#
# Login configuration initializations:
#
# ERASECHAR Terminal ERASE character ('\010' = backspace).
# KILLCHARTerminal KILL character ('\025' = CTRL/U).
# UMASK Default umask value.
# ULIMIT Default ulimit value.
#
# The ERASECHAR and KILLCHAR are used only on System V machines.
# The ULIMIT is used only if the system supports it.
# (now it works with setrlimit too; ulimit is in 512-byte units)
#
# Prefix these values with 0 to get octal, 0x to get hexadecimal.
#
ERASECHAR 0177
KILLCHAR025
UMASK 002
ULIMIT 2097152
# ^
#
regards,
Eyck
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