CentOS 5 Server :: Time On Xen VM's Drifting Ahead Of Real Time?
Aug 4, 2009
I am hosting two Virtual Servers both running Centos 5.3 on a host machine also running the same OS. The VM software in use is Xen, as supplied with the OS.The host machine's time and date is fine, however both Virtual Servers are running ahead of real time consitantly.Running /etc/init.d/ntpd restart will resolve the issue however one of these is running MailScanner and when the time suddenly goes backwards, sometimes by as much as an hour, it stops working properly.
We have a production web site running apache 2.2.3 across several web servers. we also have a major problem with SPAM comments right now. our method of identifying valid IPs (whether by external clients/customers, or internal personnel) vs SPAM'ers is not ideal - its prone to erroneously labeling legit IP's as targets to be blacklisted.
What we need is.. a way to see how much distinct request traffic is coming from any given IP address to the site in real time (or very near realtime). Essentially we want to see in some graphic/chart way requests per sec to apache / per ip sorted by requests per sec.Would nTop do this? I've only used this in a limited form at a branch office, not on a production web server.
what the recommended way to set up real-time (or near real-time) folder synchronization among 2+ servers. I looked a rsync but that doesn't sound real-time and it looks like its something that you might put in a cron once an hour.
I have a F14 laptop being used as a music server. For some reason the clock time runs fast and slowly drifts forward about 5 minutes/day.
ntpd is running. The ntpd.conf is pretty much F14 out of the box and the same as my other F14 instances that do not exhibit this problem. If I restart ntpd, it syncs up the time, but then the time slips until the ntpd seems to give up.
Initially ntpd reports it is synched,but then over time it reports being unsynchronized.
Shortly after restart:
Code: ntpdc> sysinfo system peer: w1-wdc.ipv4.got-root.me.uk system peer mode: client leap indicator: 11 stratum: 4
I used the following command to get the unix time of root user creation:
Code: awk -F":" '$1 == "root" {print $3}' /etc/shadow How can i convert this into the date/time of creation?
I am writing a shell script, which determines the OS installation date among other stuff, and i am assuming the root user's account creation date should be a pretty accurate pointer. Are there reasons why i should not be assuming so?I would be open to other suggestion for getting this date/time, but it would nevertheless be interesting to convert the unix time to "real" time without doing complex manual(or otherwise) computation..
this idea to me right now seems stupid and impractical so I'm also looking for solutions outside of this one. I'm creating a set of highly available servers. They currently utilize pacemaker to manage a shared IP address, apache management, mysql management and also drbd handling. They currently replicate, properly failover and run fine. However, this is a shared web hosting setup and everytime a new user is added to the system a username and password is created and the httpd.conf file is updated for their site. I need a way to replicate those changes to the other server. For httpd.conf I'm pretty sure I can just stick it on the apache drbd resource and create a symbolic link. However, for the passwd and shadow files that is not a realistic solution.
I am currently using curlftps to mount a directory on a ftp server locally as /backup , I then use rsync to do an incremental backup to this directory every night and a full backup at the weekend.A requirement has arose for a similar set up but one that syncs in real time, so if a user puts a file in a directory it immediately copies that file to my ftp server, in this case it immediately copies it to /backup
I'm trying to check my server's bandwidth usage in real time, installed the following programs but none worked so far.
Iptraf - No results even when using iptraf -u Tcptrack - Error : pcap_loop: cooked-mode frame doesn't have room for sll header Iftop - No results, everything 0b
Are there any programs that displays bandwidth usage in real time and actually works on VPSes? Or getting real time bandwidth usage on a VPS is simply impossible?
I have 2 servers each one with a RAID and I want them mirror they data so if one of them goes down the other one take the job with out disruption. I've heard of multipath by I want to know it in detail or learn of more options.
I would like to connect to Linux Server remotely over LAN in graphical modeBut I need access for several users in real time. Everyone must have its own desktop.
In the right upper corner of your screen,you can see if you have a network connection or not.Most of the time I do not have one according to Networkmanager (?).So I have to enable my wired connection manually.I already tried a lot to change my settings so I would have a network connection at boot,but it doesn't seem to work....Firefox is in Offline modus when I logon..
I have several file servers in our offices and I am relatively new to Ubuntu / Linux. I get notices that there are updates for the server software from time to time. Is it typical to update everything when available or should I follow "If it ain't broke, don't fix it..." mentality?I would hate for everything to be working fine and then have an update throw me a curve.
if I want to use an rt kernel in ubuntu studio, how do i use the kernel? say for instance, Ubuntu studio is installed with generic kernel.then i download the rt kernel.
I'm new in UBUNTU and would like to get a real-time antivirus.Maybe it's not necessary, but I still want it (I've got an iMAC and have installed an antivirus... ) So, please... which antivirus is good and in real-time (I mean that, if I try to open an infected file or go to a bad website, it stops it). Is KLAMav good and in Real time?
Just installed a real time kernel on my new computer so I can record music. My problem is that I have no GUI. I noted that I would not when fglrx drivers could not be installed/applied to the new kernel when installing it.
I created filesystem XFS on partition hda8 with subvolume real-time on partition hda5: Code: mkfs.xfs -r rtdev=/dev/hda5 /dev/hda8 and i mounted it: Code: mount -t xfs -o rtdev=/dev/hda5 /dev/hda8 /xfs But I don't know how can I use this partition hda5 with subvolume real-time. I don't know how to create directories, copy files to it and another. Thanks for all answers!
EDIT:in manual it is writen: The realtime section is used to store the data of realtime files.These files had an attribute bit set through xfsctl(3) after file creation, before any data was written to the file.
This script puts a natural number 5 times a second.
3. Then in the second bash window I type (as root):
Code:
The script test2 looks as follows:
Code:
While true; do true; done
During the following 15 seconds test2 is the process with the highest real-time priority. As far as I know the script doesn't perform any system calls so it shouldn't be suspended even for a minimal timeslice. My question is: why the process test1 manages to put a few numbers on the screen before test2 stops. I thought that test2 would exclusivly own the processor for 15 seconds.
I have to write one Shell script where i have to find one word in current generated log.Log name has specific format like 'NAME_DDMMYY_HHMMSS'.log.Each time i have to go and check the word in newly generated log.How can i pass the newly generated log name in my Script?
I seed a suggesting related asychron io. I'm write a program which use completion ports, but wandor how avoiding loops like for(; below...i.e I want parse proto with count in first and then computing some quantity of pieces. how that make with aio?
Running qjackctl as root allows me to run the audio in realtime so it seems to be a permissions problem and it seems to me that lubuntu does not read the /etc/security/limits.d/audio.conf file when I boot.
I have a linux router box with ubuntu which routes internet for several people. There is no extra traffic shaping, so everybody can get the whole bandwidth when its free. What I would like to have is a real time traffic counter per ip, just like a program called "iptraf" but on a per-ip basis. Iptraf can only count on a per-connection basis and thus cannot display a bandwidth that a certain ip has taken (because a single ip can start several onnections). So a console program with text interface like iptraf would be perfect - does anybody know about such a program? After some googling I came to the conclusion that such a program does not exist (which must be wrong - i think that per-ip real time traffic flow information is the first thing every router owner would like to know).
I have a log file that I would like to examine during some changes under process that writes to this log. Is there some way to open this file and read in real time changes written to it ?
First off i know that suse linux cant be infected by window based viruses and that as a whole reactive based technology such as anti virus wont be that effective as it is always dependent on the virus spreading first-but is there a way to have a real time antivirus scanner under linux? It would be nice to know if i file i opened had a nasty virus in it like the way it does in windows. I first came to think of this since the new opera browser has built in protection from avg. Ive tried opera but still prefer firefox with all the addons like noscript and adblockplus etc.
I was wondering if there's a way for me to get real-time kernel support on regular Ubuntu 9.10 through some sort of update. I know Ubuntu Studio has a real-time kernel, but I'd prefer not to use it. I'm a fan of the original Ubuntu.
