Ubuntu Linux

[SeijiSensei]

Do you see all your adapters if you type "ifconfig" at the prompt? Do they have the correct addresses? Is the alias in /etc/modprobe.conf (or in the files in /etc/modprobe.d/) for eth0 assigned to the correct kernel module ("driver")? Are these modules loaded if you type "lsmod" at the prompt? What do you see if you type "route" at the prompt? Is there a route to the default gateway? Can you ping other devices locally but not go out to the Internet?

Are the correct DNS server addresses in /etc/resolv.conf? What happens if you enter 69.42.221.126 in a browser address box? Do you see the AS home page? If so, your DNS resolution is broken, but your TCP/IP connectivity is just fine.

If DHT works, then you must have a working TCP/IP setup since DHT uses UDP to communicate.

I don't know about USB sticks and Ubuntu live-CDs. Sorry.

[WanderingKnight]

I should ask for some details on some stuff:

Is the alias in /etc/modprobe.conf (or in the files in /etc/modprobe.d/) for eth0 assigned to the correct kernel module ("driver")?

How do I check that? How do I know if that's the correct module?

Cn you ping other devices locally but not go out to the Internet?

How do I do that? I don't have any other devices that connect via ethernet.

Are the correct DNS server addresses in /etc/resolv.conf?

How do I check whether if they're the correct ones or not? I have very limited knowledge about networking, sorry.

I don't know about USB sticks and Ubuntu live-CDs. Sorry.

No problem, I solved it on myself (damn my laziness on Google searching...).

As for the rest, I'm willing to try but I'd need some details on what exactly I am looking for, since rebooting over and over to the Live CD interface (with the it implies) is not a very pleasing thought.

[grey_moon]

Originally Posted by WanderingKnight

Well, I just tried booting into a previous kernel and it doesn't work either. Any ideas on what could be the problem? Looks like Azureus' DHT system is able to connect, but seems like I can't get any TCP/IP connections at all

(BTW, another thing, how do I mount a USB stick while on the Live CD interface? It won't let me do it when I select "Mount").

try

sudo mount /dev/sda1 /mnt

[WanderingKnight]

Okay, an update here... I tried this:

enter 69.42.221.126 in a browser address box

...and I get the AS homepage. However, I tried accessing /etc/resolv.conf and it seems all right :O

try

sudo mount /dev/sda1 /mnt

Thanks, but I had already solved it

[grey_moon]

Originally Posted by WanderingKnight

Okay, an update here... I tried this:

...and I get the AS homepage. However, I tried accessing /etc/resolv.conf and it seems all right :O



Thanks, but I had already solved it

Hee hee sorry I answered your earlier post and didn't see your new one, the dangers of not refreshing

[SeijiSensei]

If you can see the home page with the IP address, but not by entering www.animesuki.com, then your DNS resolution is stuffed. I take it you're getting your information from the ISP at boot using DHCP. /etc/resolv.conf should look like this:

search some.domain.here
nameserver 1.2.3.4
nameserver 1.2.3.5

The search line is optional; it's used to append a domain to hostnames so you could say "ping joespc" rather than "ping joespc.joesdomain.com". The addresses should be coming from your ISP. See if you can ping those addresses from a terminal.

If you want to try a test, replace the first address with 12.148.244.151, a nameserver I manage. Does that help?

If you still can't resolve names, this is not a problem that's easily fixable. DNS resolution is handled through the /lib/libresolv.* libraries which are a part of the glibc libraries that come with Linux. You might try "apt-get update glibc" from the command line and see what happens. I don't use Ubuntu much so I don't have a good grasp of the package tools. There must be a log somewhere that apt maintains listing the changes to the system it's made. Perhaps some other Ubuntu user here knows where it is? You could see what else changed along with the kernel, since we now know the kernel upgrade is not at fault.

As for the modules, though they're working fine for you, there will be a line in modprobe.conf that looks something like:

eth0 b44

which tells Linux to load the Broadcom adapter module called b44 to support eth0. The module referenced will obviously depend on the card you have. All the network drivers live in /lib/modules/2.x.x-something/kernel/drivers/net.

[WanderingKnight]

Okay, thanks for the help, but I just ended up reinstalling. Now that I think about it, recompiling the kernel could have worked, but I was just kind of tired and didn't want to push things too much. At least reinstalling Linux is much more painless than reinstalling Windows.

Thanks anyways

[SeijiSensei]

I doubt recompiling the kernel would have helped since you could connect with the kernels you had if you used IP addresses; you just couldn't resolve names. As I said, resolution is handled by different libraries than those found in the kernel code. I guess it's possible that your glibc libraries could have been out of sync somehow with the kernel, but I've never seen that problem.

My next suggestion was a reinstallation. Are you using the stock Feisty install, or did you tell it to update your installed software? Did everything work okay after reinstalation + updating?

[WanderingKnight]

I doubt recompiling the kernel would have helped since you could connect with the kernels you had if you used IP addresses; you just couldn't resolve names. As I said, resolution is handled by different libraries than those found in the kernel code. I guess it's possible that your glibc libraries could have been out of sync somehow with the kernel, but I've never seen that problem.

My next suggestion was a reinstallation. Are you using the stock Feisty install, or did you tell it to update your installed software? Did everything work okay after reinstalation + updating?

Yes, I just updated the kernel and it works fine. On second thought, I'm kind of certain the problem was caused due to the hard reboot when updating the kernel... or something like that. I know the damn hard reboot broke something, whatever it was, and it had to happen just when the kernel was updated.

[grey_moon]

Improving the speed of Ubuntu...

Right lets start with the usual, since installing Ubuntu my wee 1.5GHz celeron has a new lease of life, but still if I slug out its memory it starts getting sluggish as soon as it starts swapping. Of course no way as bad as it used to slug with XP Home.

I noticed this normally after I have left my lappie on for weeks and then I've been doing some gimping which understandable pushes it to swap. My memory was dropped from 1.5GM to 756MB due to memory problems.

Well I've upgraded the memory, but still the issue of swapping, so I've started investigating and discovered the function of swappiness. Basically how long before the kernel starts swapping.

https://help.ubuntu.com/community/SwapFaq

By default Ubuntu is set on 60, where 100 is swap as soon as possible and 0 is swap as late as possible. Now the faq recommends 10. Now I've made the change, but with my upgraded memory I'm not too sure if I will ever notice a difference.

So thoughts on this, and more importantly does anyone want to join me in the quest to make Ubuntu faster?

[WanderingKnight]

I dunno... I usually leave the PC turned on for weeks, or even months, and I've never noticed any sluggishness when compared to when it's just booted... and I have only 512 MB of RAM. I did notice a speed up when I reinstalled the system two or three days ago, though.

[SeijiSensei]

My last PC had 512M and ran KDE on Fedora without any noticeable delays due to swapping.

Does Ubuntu set up a dedicated swap partition on the hard drive (or a dedicated logical volume if it's using LVM)? I've only installed it once before and don't recall what happened by default. I always allocate a dedicated partition or LV to swap and usually size it at 2X physical memory.

On my current 1GB machine running X+KDE plus a bunch of applications (Azureus, Firefox, Thunderbird, GIMP, OO Writer, some terminals, and few instances of Konqueror), I get the following memory usage stats from running "top":

Mem: 1035032k total, 1015436k used, 19596k free, 10108k buffers
Swap: 2003564k total, 137372k used, 1866192k free, 308308k cached

Notice that most of the physical memory is in use, but 300M is actually devoted to disk caching. As programs need more memory the cache will shrink, so I'm a long way from running into swap. The little swap I am using mostly contains kernel processes that swap themselves out when initially loaded. You can see these processes if you run "ps ax"; they'll appear in brackets like [ksoftirqd].

(If you want more detail on memory use, "cat /proc/meminfo" has it all.)

I'm running with "swappiness" set to 60 as well.

[WanderingKnight]

I don't know what happens by default, whenever I installed it I did manual partitioning. I have 1 GB of disk space assigned to a swap partition.

[grey_moon]

Yah I've got 1GB of dedicated swap partition, but now I have ~1.5GB of memory. It's interesting to note that the faq states that the swap is used for hibernation. I wonder if that is the reason why the old recommendation is 2 times your physical memory?

My hdd is a lower 5400 one but I wouldn't have thought that would have made my lappy noticeablely sluggish with swapping would it? I guess I need a hdd benchmark to be sure.

sudo hdparm -t /dev/hda

/dev/hda:
Timing buffered disk reads: 98 MB in 3.02 seconds = 32.41 MB/sec

What are the speeds of your drives?

@sejisensie - thanks for the cat /proc/meminfo I used to just use free -m, that one provides much more interesting info

[WanderingKnight]

Could be due to that. Here's the benchmark of the disk with my swap partition:

/dev/sda:
 Timing buffered disk reads:  156 MB in  3.01 seconds =  51.79 MB/sec

Can't remember its exact RPMs. There's also the thing that it's a SATA and not an IDE drive like yours.

[grey_moon]

Originally Posted by WanderingKnight

Could be due to that. Here's the benchmark of the disk with my swap partition:

/dev/sda:
 Timing buffered disk reads:  156 MB in  3.01 seconds =  51.79 MB/sec

Can't remember its exact RPMs. There's also the thing that it's a SATA and not an IDE drive like yours.

Thank you WK, I just checked my server box and that is sata 'd up and that have an average of

/dev/sda:
 Timing buffered disk reads:  228 MB in  3.01 seconds =  75.86 MB/sec

/dev/sda:
 Timing buffered disk reads:  222 MB in  3.02 seconds =  73.56 MB/sec

/dev/sda:
 Timing buffered disk reads:  232 MB in  3.01 seconds =  77.10 MB/sec

It's hard to see if this means anything as I think my main problem is I am looking for slowness, so any change in speed is probably amplified by my mental state...

[WanderingKnight]

The 3 Ubuntu CDs I ordered two weeks ago came on the mail today.

I'm happy

[SeijiSensei]

OK, I'll bite. Why did you have them sent to you when you can download them from torrents or HTTP/FTP and burn your own?

[WanderingKnight]

OK, I'll bite. Why did you have them sent to you when you can download them from torrents or HTTP/FTP and burn your own?

Mostly for the packaging. It's nice and shiny

Besides, there's the thing that I burned quite a lot of Ubuntu CDs and I've got them all scattered around, and many of them don't work. The last time I had to install it (with this little problem with my internet connection), I was lucky to have a Debian Netinst CD laying around or I wouldn't have been able to install it, since every CD I had was trashed. The Live CD I was using to browse died after a couple of uses.

[grey_moon]

I buy the SuSE CD's every so often to say thank you