Prix's questions

I have to setup 2 servers with RAID 1 and the company cannot provide funds for the hardware needed until december, here is the hardware available:

Computer A

• OS: CentOS 6.0
• MB: EP41-UD3L
• RAM: 4GB
• CPU: E4300 1.80GHz

Computer B

• OS: CentOS 6.0
• MB: EP45C-UD3R
• RAM: 4GB
• CPU: Q9550 2.83GHz

I have 2 hardware cards Silicon Image SiI 3132 available that was laying around the stock, if that is any worth using.

Now the questions:

• If I use software RAID is it possible to convert for hardware RAID later or how difficult would that be ?

• Should I use the Silicon hardware of each Motherboard software raid instead ?

• Heard that silicon is just a fake raid and even on the device name at the OS you can read SoftRaid, so would I gain any benefit from using it ?

• If possible would love to hear some raid hardware recommendations on the range of USD80 avg if there is any worth using that is probably the funds they will hand us for each card.

I have a Windows 2003 cloud server and I did like to checkout the current usage of cpu and memory of 2 applications I have currently running but I am not sure of what would be the right tools to check these out on a VPS server.

What tools should I consider using to verify CPU usage at the current moment, not statistic?

I am looking for some information in regards DDoS in the follow scenario:

I have a server that is behind a Cisco Guard and it will be DDoS'ed, I only care about a set list of IPS that by not means are the attackers.

Is it possible to null all other ips but this list to actually get any response to my server or in the long run no matter what I do if they have enough DDoS power I will just go down like a flie ?

Is there any recommended company out there that can actually cope with a DDoS ?

My server will mainly run several clients that will get connected to a external server and all it needs access to is my local MySQL the the private network so I can access it.

There will be no other services runnings such as web or ftp etc at least not to the external ips of the server if i ever have to have any of these service they will be on the private network.

The MySQL will be available externally only to 1 safe ip not known by anyone but me and internally at localhost + private network.

Are there any solutions ?

Is it possible to have an IP to act as a local IP in different countries ?

For example the ip 193.105.173.105 which seems to be located in US but is handled by RIPE.net

Internet Assigned Numbers Authority (IANA) says that RIPE NCC handles Europe, the Middle East, and Central Asia.

So im quiet at loss on what they are doing would appreciate if some one were able to explain me how is the connectivity done in this case and how ?

Taking a closer look at the tracert all I can really see is NA but yet that ip information is handled by RIPE.

Let's consider A (client) and B (server) where A makes download from B.

• How much can a bad routing from A to B affect the download speed ?

  A traceroute from A to B returns a path that is 10 hops long, with a round-trip latency of 300ms. It also shows ~10% packet loss at hop four. Under normal conditions, the average round-trip latency between A and B is between 10ms and 30ms.

• Could this sort of impact reduce A download speed drasticaly or as long as both side and routes have enough link for the full speed of A from B and vice-versa it should maintain the same speed ?

• Besides tracert and the ping analyse of A to B what else is used to identify the problem ?

If you need extra information please let me know.

I currently have 2 links of 20 Mbps on my hand and wanted to test them internationally and nationally.

I already have the 2 national links for test but am having problems finding some good international link with 100/1000 Mbps link that will allow me to get the max out of these 2 links I have.

Would appreciate if you guys could point me out some sources that would fit this.

I don't want to avoid doing a fsck, but I would like to know if there is a better approach so it doesn't take ages to complete the process when it runs after a reboot 180 days later.

If you had it ran 20 days ago and then do it again, will it be faster or it does a full check all the time and it would be meaningless to do such thing ?

What would be the best practice to keep it up to date and yet minimize the time it takes to recheck each run ?

I have some files in my server that I wanted to make a patch for, so I took one of the files to test:

cp /path/file ~/file

So now I have just the same file in my root directory so I make any changes I need on the file at ~/file and now I run the diff command on the 2 files:

diff -Nuar /path/file ~/file > my_file.patch

I have also tried:

diff -u /path/file ~/file > my_file.patch
diff -c /path/file ~/file > my_file.patch
diff /path/file ~/file > my_file.patch

Now as you can see there is no differences on the files besides what I have just changed on it but instead of creating a my_file.patch with only the code to patch the changes I made into /path/file it always create a full file with all the content of /path/file marked to be removed and the content of ~/file marked to be added.

Then I try to apply the patch:

patch -p0 < ~/my_file.patch

And it fails badly ... it always print out a reject file with all the content just like the file is.

I am running out of ideas to why it is doing this all the time, with a few files I can produce a patch without problems but with most of the files on the system that I need to make one it won't work at all.

Any ideas on what could be the problem ? encoding, format ? solutions ?

I am not system administrator, but I have nice knowledge of Linux, Unix, Windows and hardware.

What are the most needed topics that a Linux Administrator has to know by heart (at the point of being able to fix, setup, work it out without having to read the manual at the max; checking the man pages which are common with any distribution)?

The FOCUS I'd like to set for this would be from company network to server administration which may have some equal features will most of the time have some different ones as well. Like for example you won't always see an FTP server for a company server but probably see Samba most of the time...

I am not saying "book you must read" or things like that, but I meant the most necessary features that will probably be needed in your daily life as a Linux administrator.

Like:

1. Kernel, iptables
2. Sendmail, Postfix, qmail, exim
3. Squid, Samba, NFS, LDAP
4. Apache, ngxix, lighthttpd
5. vsftpd, proftpd
6. bind
7. Daily problems faced
8. What is the feature you used the most during the day

This is not an in-order list nor the most needed. It just names something that came to my head.

PS: I already have the basic knowledge, but I don't have a daily experience on the field. I have had servers, made some networks, and so on. Further I even have some deep knowledge in some portions of it. I just wanted to update this here, like I said this is more of a DAILY LIST OF A LINUX SYSADMIN LIFE.

I would appreciate if you guys/gals could list topics and for example which field inside it is the most used or important to memorize.

If you believe my question is unfit just let me know about it and I will delete it myself or if you feel it is fit but needs to be re-worked more let me know as well and I will try my best.

i am not very familiar with raid partitons and am not even sure if this is the right place to ask about it, but i hope that if it is not that some one can point me on the right direction.

This is my situation, i have 2 500 GB hds and a 3ware pci-e hardware for raid and i wanted to make a RAID 1 but i dont know if i can make more then one partition for it, for instance:

MAIN HD: os partition: 100GB data partition: rest of left size

and make the RAID 1 either work on all the HD or just on the data partition of it.

that is on windows xp sp3 and the 3ware allows bootable raid.