System freezes when using FTP

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Oct 11, 2011
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Hello!

Recently one of our servers started freezing when someone tries to upload/download multiple files over FTP.

I tried downloading a Wordpress install via FTP, and it gets to about 400 files of 1000 before it freezes each time i try. The server will not respond in any way and i have to do a hardware reboot in order to get it back up again.

Anyone that might have some idea what the problem might be?

My first thought was the tmp directory, but when i run:
Code: 
df -h

i get:
Code: 
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda3             435G   12G  402G   3% /
tmpfs                 2.0G     0  2.0G   0% /lib/init/rw
udev                  2.0G  104K  2.0G   1% /dev
tmpfs                 2.0G     0  2.0G   0% /dev/shm
/dev/sda1             473M   16M  433M   4% /boot

So the system and most certainly the temp directories is barley used at all!
 
I just tried to download the files in 3 sections. Last section on approx 200 files and 4,2 MB freezed the server.
 
I have CSF running on this server so i thought there might be a block going on. But the server is not responding from another IP either... so i still think it freezes.
 
I adjusted CT_LIMIT 400 -> 500 in config for CSF and it seems to work fine now.

Weird that the server was not responding from my iphone though... must have been something else going on at the same time since my phone and computer is on totally different networks.
 
Hello,

You'd better check your hardware, and start with HDDs:

Code: 
smartctl -a /dev/sda

What does it show?
 
Hi, I have the same issue but not about ftp issue. My issue is my server keep going down rarely and I have email my server provider to reboot the system to get the site backup any reason why it keep going down. I get message on my Directadmin

This is an automated message notifying you that the 5 minute load average on your system is 192.76.
This has exceeded the 10 threshold.

One Minute - 311.54
Five Minutes - 192.76
Fifteen Minutes - 85.41

top - 00:28:59 up 17 days, 4:12, 0 users, load average: 346.96, 216.51, 97.91
Tasks: 648 total, 1 running, 645 sleeping, 0 stopped, 2 zombie
Cpu(s): 4.1%us, 0.3%sy, 0.0%ni, 95.1%id, 0.5%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 4053396k total, 4024268k used, 29128k free, 6940k buffers
Swap: 7811064k total, 2197684k used, 5613380k free, 28400k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
19392 root 20 0 19460 1720 908 R 6 0.0 0:00.03 /usr/bin/top -c -b -n 1
50 root 20 0 0 0 0 S 2 0.0 0:01.93 [kblockd/0]
18339 apache 20 0 129m 31m 5164 D 2 0.8 0:01.09 /usr/sbin/httpd -k start -DSSL
1 root 20 0 8352 460 424 S 0 0.0 0:08.40 init [2]
2 root 20 0 0 0 0 S 0 0.0 0:00.00 [kthreadd]
3 root RT 0 0 0 0 S 0 0.0 0:02.45 [migration/0]
4 root 20 0 0 0 0 S 0 0.0 0:03.26 [ksoftirqd/0]
5 root RT 0 0 0 0 S 0 0.0 0:00.00 [watchdog/0]
6 root RT 0 0 0 0 S 0 0.0 0:00.06 [migration/1]
7 root 20 0 0 0 0 S 0 0.0 0:01.48 [ksoftirqd/1]
8 root RT 0 0 0 0 S 0 0.0 0:00.00 [watchdog/1]
9 root RT 0 0 0 0 S 0 0.0 0:00.02 [migration/2]
10 root 20 0 0 0 0 S 0 0.0 0:00.72 [ksoftirqd/2]
11 root RT 0 0 0 0 S 0 0.0 0:00.00 [watchdog/2]
12 root RT 0 0 0 0 S 0 0.0 0:00.00 [migration/3]
13 root 20 0 0 0 0 S 0 0.0 0:00.37 [ksoftirqd/3]
14 root RT 0 0 0 0 S 0 0.0 0:00.00 [watchdog/3]
15 root RT 0 0 0 0 S 0 0.0 0:00.11 [migration/4]
16 root 20 0 0 0 0 S 0 0.0 0:10.47 [ksoftirqd/4]
17 root RT 0 0 0 0 S 0 0.0 0:00.00 [watchdog/4]
18 root RT 0 0 0 0 S 0 0.0 0:00.29 [migration/5]
19 root 20 0 0 0 0 S 0 0.0 0:02.91 [ksoftirqd/5]
20 root RT 0 0 0 0 S 0 0.0 0:00.00 [watchdog/5]


================================
Automated Message Generated by DirectAdmin
 
Last edited:
If your system freezes then you have bad hardware.
 
tokyosama said:
Hi, I have the same issue but not about ftp issue. My issue is my server keep going down rarely and I have email my server provider to reboot the system to get the site backup any reason why it keep going down. I get message on my Directadmin
Click to expand...

scsi is probably right. Check your hardware, or ask your DC to do it. Note, some of us here is ready to give you a commerce service and help you sort the things with your issue. Feel free to hire some of us, as you server need some diagnostics to be done.
 
I'm not as quick to blame it on hardware, though it certainly could be. Your server load is going up very quickly, and your used swap space is high. If your server is using a lot of swap space there's going to be a very high server load while the server continually swaps memory in and out of swap. Why? I don't know. Try to figure out what's running when this happens. You might want to create a cronjob to send you the output of top every five minutes or so an email. Then filter them into their own folder in your mail client. Then the next time the server goes down look at the preceding few top output emails to see if you can tell what's running and increasing the swap usage.

How often is it rarely? It might be bad memory, which only shows up when you've used a lot of memory.

Can you ping the server when it freezes?

Jeff
 
@Jeff,

doesn't it seem to you a little bit strange to have 95.1%id and load average: 346.96, 216.51, 97.91 (up 17 days)? And 645 sleeping processes? Why do they sleep? I'd definitely check HDDs and RAM of course.
 
Yes but the load may be caused by lots of stuff in swap which is being switched in and out. I've seen that. Certainly I'd recommend searching for other reasons before swapping out hardware, which could be expensive.

I just had this thought: it could be bad memory; then the server would run fine until it started using the bad memory.

One important diagnostic procedure is to create a cronjob which appends the current date and time to a file every minute. then you could see if the machine were really hanging or not, by looking at the file after a reboot. If the machine were really hung the posts would stop when the server was unreachable, but if just slow, then you would probably continue to at least some posts to the file after rebooting the server.

Jeff
 
Hi my server went down again when i received an email my system load average is 29.92 I email my server provider to reboot the server. My server is running on Intel i5 and 12 ram could it be an bad hardware then
 
Hello,

It can be ...and can not be. Why are you asking such questions here? You'd better ask your DC for help either... or hire somebody from these forums. Note, none of us is any kind of fortune-teller, so we need to login as root and do some diagnostics, as you did not provide us enough information and results of any tests.
 
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