I have a disk in raid, but it seems raid is not working correctly. I took it out, and plug into another server without raid. However, fdisk shows error
Quote:
#fdisk /dev/sdb device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel Building a new DOS disklabel. Changes will remain in memory only, until you decide to write them. After that, of course, the previous content won't be recoverable.
The number of cylinders for this disk is set to 20023. There is nothing wrong with that, but this is larger than 1024, and could in certain setups cause problems with: 1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs (e.g., DOS FDISK, OS/2 FDISK) Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
Command (m for help):
Should I correct the partition table now, or should I put it in another raid for checking?
i have centos 5 server i want install xen on it on my server is just one partion how may i resize this partion( without format partion/with put delete data) and then create lvm partion?
Going to order a new server fairly soon, and I'm facing the tough question if I should go with 64-bit or stay with the "classic" 32 bits. My operating system of choice is Red Hat Enterprise 4.
From the research I've done, RHEL 4 (64 bits) should come with dual libraries that would allow running 32 bit and 64 bit applications under the same 64 bit operating system. Sounds great, and if it comes with an overall performance boost I am all for it.
But I've also heard that that's only the theory - in reality, I could end up banging my head against the screen for uncounted hours because compatibility still isn't as good as it's supposed to be. I don't plan to run Plesk or Cpanel, but I still don't want to get into hot water with other applications I've been using on my current 32-bit server.
All in all it's intimidated me quite a bit, so I'd probably go with 32 bits this time around, just to be on the safe side. Then again, I'm still having an eye on the possible performance boost, so dunno. Does anyone have an idea what's the latest on this? 64 bit already safe for the non-experimental-minded, or bleeding edge and stay away from?
Anyone out there have experience with SuSE over RedHat? RHEL is obviously the generalized Enterprise version used across most commercial hosting companies, but I'm interested in hearing about some SuSE experiences people have had.
It looks like SoftLayer offers SuSE and a couple VPS hosting companies do the same. I'm wondering how many large-scale sites are run on this operating system.
With Red Hat Enterprise Linux 4 (RHEL 4), are updated packages made available, or are only security patches backported? Specifically I'm interested in vsftpd. Version 2.0.1 is included in the RHEL installation on a server I'm working on, but there is a bug fix in v2.0.4 that I'd like to get access to.
Is there an easy way for me to browse / search what packages are available for RHEL 4, preferably via website?
I have a problem with time at one RHEL 4 server, it is a plain box, and from time to time the time (hours) seems to be auto modified, no one is touching the box and then from once it got modified to a few hours less than what we specified, to change time and date we always use:
Code: date --set "2007-10-24 13:35" hwclock --set --date="2007-10-24 13:35"
The only thing that I noted is that ntpd daemon was running, while in the rest of our plain box it is not running, maybe this is the reason the system is auto chaning the time?
Is there a Windows GUI software for remote Admining servers that run on Red Hat Linux?
FYI: Currently I use Putty for remotely managing our servers.
So if you can recommend a GUI like Windows desktop software for remotely Admining servers running Red Hat Enterprise, I would very much appreciate that.
FYI: we have like 10 dedicated severs, so a desktop GUI that would allow one to monitor/manage multiple servers would be best. But if the GUI that you think is best can only remotely connect/manage one server at a time, requiring disconnecting to connect to the other server to Admin it, that is fine.
Also, I would love to hear what you think is the best book, best tutorial and reference guide for remotely Admining servers running RHEL? I am not looking for one of those books that are 1000 pages, but something that is a few 100 pages and can be read in 1 month assuming a few hours per day of reading.
For the past two weeks, our Hypertown RedHat RHEL 5.2 server has been going down everyday because of a wierd Kernel Panic problem.
Attached you can see what was displayed on the console at the time of the panic. This is what SoftLayer tech. support team was able to obtain from the console.
I seen where a lot of server management companies are charging big bucks for this, so this might save you some time and money. First
Code: nano -w /etc/yum.repos.d/dag.repo Insert
Code: [dag] name=Dag RPM Repository for Red Hat Enterprise Linux baseurl=http://apt.sw.be/redhat/el$releasever/en/$basearch/dag gpgcheck=1 enabled=1 Then yum update and search for ffmpeg and install all ffmpeg packages including devel. Seems there is some lib problems along the way so in /etc/ld.so.conf add /usr/local/lib then ldconfig -v To install the php extension follow the simple directions on [url] Then you should be all set!
Tried and tested on 2 different centos server, works fine.
I have 2.4.x version installed on RHEL and I need to install same version on Solaris 10. How can I find out what packages/modules were compiled for RHEL so that I can download same for Solaris and compile them.
As cPanel is an integral part of server hosting and has the ability of compiling Apache 1.3.x with PHP4 (cgi) and PHP5 (dso) on your server OS.
Does anyone know or have baselines/benchmarks for which performs better generally for hosting: 32bit or 64bit RedHat 5 when cPanel 11 has compiled for the Apache and php mentioned above on either of these OS editions? (assume latest versions of apache/php4/5)
I was wondering if 32bit performed better or 64bit on a quad core Xeon. Don't forget PHP is compiled for prefork and not multi-threading for Apache 1.3.41 (which are considered legacy 32bit forked apps compiled against 64bit OS).
Or rephrased, could i be hampering performance by running it on a 64bit OS on a Xeon (X3210) or improving performance? I'd assume 64bit would offer better all round processing power, or is this a misconception.
I recently decided to get a server on RedHat Enterprise 5 X86_64 (64bit), when i wondered if 32bit version would have provided better performance and been the better options for compatibility.
I just got a Dell 1600SC dual xeon 2.8 from the Planet with a Dell DRAC3 remote access card. In my RHEL3 system this hardware combination works great, but in the new RedHat Enterprise Linux 5 system the DRAC accepts no keyboard input after RHEL5 loads, thus making it impossible to login to the OS through the drac remote console redirect. Tech support suggested it was because the RedHat Enterprise 5 and CentOS5 kernel does not load the PS/2 keyboard driver which is required for the Drac3 to accept keyboard input. (a drac4 works, but that's not an option for this server I would guess.)
At tech support's suggestion, I added atkbd.set=2 to the /boot/grub/grub.conf file rebooting had no change - still text input to enter the bios, but no text input to login to the OS. I also added serial --unit=0 --speed=9600 -word=8 --parity=no --stop=1 terminal --timeout=2 serial console which I saw in /etc/grub.conf (which is not linked to /boot/grub/grub.conf but instead a separate file) but still no luck - no keyboard input accepted through the drac3 remote console to login to the os through the drac console redirect.
Has anyone solved this hardware/software combination? Or is RHEL5 simply not going to be backwards compatible with the Dell DRAC3 hardware?
Any ideas, suggestions, or solutions would be greatly appreciated as I've been working on getting a solution for this for a week now and no closer at this point.
I would really like to have the DRAC as a backup connection with my server incase any firewall or software update issue ever prevents me from connecting via ssh. I hate to have roll back to an older OS though to get it. I'm stuck.
What would cause a Linux server to run out of swap? Would it be a memory leak? This happened today to my server and it had to be forcefully rebooted by the data center.
Opcode caches have stability problems with some PHP apps:
[url]
I've been trying to get XCache working with gallery2, right now apache has to restart every 2-4 hours but it's been worse at times and it'd be nice to know what's going on
I noticed that both XCache and eAccel use a small amount of swap space all the time, it grows slowly and if I'm lucky enough to go without a segfault it will reach maybe 4MB. That's not a lot but it doesn't happen at all without a PHP cache (swap stays locked at 72kb unless RAM runs out and the server thrashes).
Here's the error and my settings:
[Tue Feb 19 06:19:55 2008] [error] PHP Warning: Invalid argument supplied for foreach() in /home/cityv4/public_html/gallery/modules/customfield/classes/CustomFieldHelper.class on line 233 [Tue Feb 19 06:19:55 2008] [error] PHP Warning: Invalid argument supplied for foreach() in /home/cityv4/public_html/gallery/modules/customfield/classes/CustomFieldHelper.class on line 233 [Tue Feb 19 06:19:56 2008] [notice] child pid 31028 exit signal Segmentation fault (11) [Tue Feb 19 06:19:56 2008] [notice] child pid 10638 exit signal Segmentation fault (11)
I have purchased several VPS from a provider and found they do not provide swap space with VPS, and even with 256MB ram, I get 'out of memory' trying to compile a perl library... Creation of a swap file by myself doesn't work (operation is not permitted). Hosting providers runs HyperVM.
So the question. Is it common or is it a misconfiguration? For now I got just 'checking on this for you' and three days of silence from their support.
I'm not opening hosting provider name, but I will if they say "You must pay for more RAM", just because other 5 VPS providers support my VPS servers with swap space.
I have talked with the moderators and they have agreed that I can start a new thread to clarify the issue of Xen and swapping as long the discussion remains technical.
For people who are curious, I would first like to explain why this is important. What we have here is someone making a specific technical accusation against Xen, and if it is indeed crucial, it needs to be solved, or otherwise people have to know it before they get into Xen.
Claim Number 1: The original claim is that users can create arbitrarily large swap and this can lead to the equivalent of overselling.
Fact: Arbitrarily large swap has absolutely zero effect on a normal system, since Linux treats swap as an auxiliary storage, and will not use it unnecessarily. Linux will always use the RAM to the full, but swap is used only when all the buffers have been cleared. If you run free on a dedicated hardware, you will see that swap usage is most of the times zero, even though you have assigned a very large swap to the system. In fact, you can try this by simply increasing the swap to very huge value, you will see that Linux will ignore it completely.
For large swap to cause a problem, the user not only has to assign a large swap, he has to run a really huge workload on his limited RAM, and this being physically impossible, will cripple his vps long before it has any serious impact on the host.
I think the above has been agreed to by the person who made the initial claim.
Claim Number 2 Merely having a swap can lead to vps getting slowed down.
Fact ; The use of swap does not mean thrashing .
Thrashing is a technical term, and it means that the application is registering a swap hit every few instructions. This is rare in normal systems, because of a property of programs that execution is always localized. That is, at any particular time, a certain portion of the program will be continuously being executed, and other portions would be idle. Linux has algorithms that will swap out the Least Recently Used page, and this will mean that the system will not run into too many swap hits.
Now again, like in the earlier case, there will be trouble if the vps customer is trying to run a 1GB workload in a 64MB RAM. This will actually cripple his vps, which is what's the right thing to happen. So normal usage of Swap will not lead to disk I/O, since Linux has explicit algorithms to reduce swap usage.
So for minor OverUsage of memory:
For virtuozzo: the application will crash
For Xen: there will be a very minor degradation of quality. And sometimes it won't have any affect at all, since as I said, just because swap drive is non-empty doesn't mean that linux is constantly swapping out.
So summarizing:
a) Inordinately large swap has zero effect on Linux
b) Non-empty swap doesn't mean that the system is registering swap hits. For normal workloads, the swap hits will be very minimal.
And an extra advice is that if you are using Xen, don't ever use snapshoting, as it will double the disk I/O, and the worst thing is that the vps that's causing this will not even be penalized. The overhead will be completely borne by the system.
