Slow Network (im feeling ripped off here!)

[RicD]

I have a few questions relating to a network I use that seems slow sometimes and not other times.

One Server has about 30 or 40 computers running off it. Only 3 of these computers take a lot of the bandwidth up, because they copy data from CD's to the main hard drive on the server. Of course this means all this copied data has to go down the cables to the server, it is an Ethernet setup running at "100Mbps".

Hang on, 100 Megabytes per second?! No chance! I copy data from a CD to the main drive and it takes about one minute per 100 Mb of data. This setup says it runs at 100 Meg a second, so whats going on?

Now, a CD-ROM can only physically copy data over to anything (your HDD, an external drive etc) at about 7.5 Mb a second! So even when all 3 computers are copying data across, it still only adds up to about 23 Mb a second, so this is four times less that the network can handle! Yet its slow.

Once this data is on the main drive, it must be then "imported" into a program on the users PC. Again, at times there could be 3 computers importing data, but all 3 computers running together means hardly any work gets done!

Example - In an 8 hour shift, 3 people all working together managed to make a pathetic 300 - 400 prints (it is a photo lab). You are supposed to make 250 yourself in an 8 hour shift, not 100.

One person had access to the network by himself and used a PC alone to print for 8 hours. Despite all the office computers still running and him only shutting down the other two printer computers, he managed to produce over 600 prints in 8 hours!!! Compared to 100 prints in 8 hours if all 3 machines are using the network.

So the question is, how can these 3 computers be made to run as fast as one does on its own? They share a database, there is no way each PC can be given its own database, its not an option unfortunately.

Its annoying when you think you have a network running at 100Mbps that actually will not even run at a quarter of this speed.

Only problem is - we have 3 processors costing £40,000 each, 3 computers costing £1500+ each and are realising that maybe we only need one PC and 1 processor. I don't wanna be the guy who tells the bosses that one person on his own can produce six times more work that three people in the same time, it wouldnt go down too well to tell them they have spent £80,000 when they didnt have to!

So, whats faster than 100Mbps? How can these 3 computers work fast together?

Using Kodak LED digital printers/processors, Halse pro Edit software, 52x CD drives etc, your standard setup really.

Any help would be appreciated as I 'only work there' and are pi$$ed off at people getting huge piles of work done alone and getting all the credit for it when its the system that lets you go fast alone!

Thanks.

[Spider]

If your not running multi-port switches then the load isn't balanced and
the bandwidth is not going to be spread evenly.

Do you have switches on the rack?

eg;
http://www.fulltel.it/scheda.php?id=3114

[z1p]

I have a few questions relating to a network I use that seems slow sometimes and not other times.

One Server has about 30 or 40 computers running off it. Only 3 of these computers take a lot of the bandwidth up, because they copy data from CD's to the main hard drive on the server. Of course this means all this copied data has to go down the cables to the server, it is an Ethernet setup running at "100Mbps". full or half duplex?


Hang on, 100 Megabytes per second?! No chance! I copy data from a CD to the main drive and it takes about one minute per 100 Mb of data. This setup says it runs at 100 Meg a second, so whats going on? mbps is mega bits per second. "B" is usually used for BYTES and "b" is used for bits.

Now, a CD-ROM can only physically copy data over to anything (your HDD, an external drive etc) at about 7.5 Mb a second! So even when all 3 computers are copying data across, it still only adds up to about 23 Mb a second, so this is four times less that the network can handle! Yet its slow.
It should be 7.5 MB per seconds, which is 7.5 mega bytes per seconds (or 60 mega bits per sec)

Once this data is on the main drive, it must be then "imported" into a program on the users PC. Again, at times there could be 3 computers importing data, but all 3 computers running together means hardly any work gets done!

Example - In an 8 hour shift, 3 people all working together managed to make a pathetic 300 - 400 prints (it is a photo lab). You are supposed to make 250 yourself in an 8 hour shift, not 100.

One person had access to the network by himself and used a PC alone to print for 8 hours. Despite all the office computers still running and him only shutting down the other two printer computers, he managed to produce over 600 prints in 8 hours!!! Compared to 100 prints in 8 hours if all 3 machines are using the network.

So the question is, how can these 3 computers be made to run as fast as one does on its own? They share a database, there is no way each PC can be given its own database, its not an option unfortunately.

Its annoying when you think you have a network running at 100Mbps that actually will not even run at a quarter of this speed.

Only problem is - we have 3 processors costing £40,000 each, 3 computers costing £1500+ each and are realising that maybe we only need one PC and 1 processor. I don't wanna be the guy who tells the bosses that one person on his own can produce six times more work that three people in the same time, it wouldnt go down too well to tell them they have spent £80,000 when they didnt have to!

So, whats faster than 100Mbps? How can these 3 computers work fast together?

Using Kodak LED digital printers/processors, Halse pro Edit software, 52x CD drives etc, your standard setup really.

Any help would be appreciated as I 'only work there' and are pi$$ed off at people getting huge piles of work done alone and getting all the credit for it when its the system that lets you go fast alone!

Thanks.

To help any network bottlenecks you could setup up a dedicated network for the PCs doing the heavy transfers. Connect the PCs to a switch via 100baseT and connect the server via 1000baseT (gigabit ethernet). Make sure all the network interfaces are set to full duplex.

This way each PC can transmit at CD rom speeds and the network connection to the server can receive the combined data throughput.

This should address any network bottlenecks, but if there are any bottlenecks at the server they would still be a problem.

[Xircom]

Well z1p that the best responce I have read in a long time. I can make no further comments and leave this one alone.

[RicD]

Thanks, I dont know about half or full duplex, I think they had it running at 200Mbps somehow, two x 100Mbps. This had to be cut to 150Mbps. Not sure about a lot of it, thats why I posted here!

For all I know the server could be dedicated to the three computers that print the photos but I doubt it, there are probably 40 or 50 wiires coming out of the server, which is just a rackmounted thing, hewlett packard I think.

I heard somewhere that a "Gigabit" setup can give you 10x more - 1000Mbps, is this an expensive option? Silly question I guess since its 10x better?!

To be honest, although this isnt so honest, I would rather let them struggle at work because I can get loads of overtime in for christmas whilst its slow!!

I could just say "Turn off 2 PC's and then, let four ppl do four 2 hour shifts or something like that, using only one PC, sending the first job to the first printer, second to the second and third to the third (just so one machine isnt having all the work put through it because the processors are way slower than images that get queued up to be printed, heh, when 1 person uses it that is!)

Thanks for taking the time to read and reply ;)