Some common Linux kernel processes
kjournald Commits ext3 journal updates to disk
kswapd Swaps processes when physical memory is low
kreclaimd Reclaims memory pages that haven’t been used recently
ksoftirqd Handles multiple layers of soft interrupts
khubd Configures USB devices
There is one kjournald for each mounted ext3 filesystem.
Among these processes, only init is really a full-fledged user process. The others are actually portions of the kernel that have been dressed up to look like processes for scheduling or architectural reasons.
Tags: Common, Kernel, linux, processes
How can I lower the TTL value in Plesk?
1. Login to Plesk.
2. Click on Domains.
3. Click on the domain for which you wish to lower your TTL.
4. Click on DNS Settings.
5. Click on SOA Record.
6. Set the desired TTL value.
TTL, or Time-to-Live, is the length of time for when a zone file is set to expire. This is usually expressed in number of seconds.
If you ask your local DNS server (usually provided by your ISP) for an Internet address, the server will figure out where to find an authoritative answer. Once provided the answer, it will keep the answer in a local cache so that if you, or someone else, ask for the same address again it will not need to make the request again.
When domain administrators configure their DNS records, they decide how long the records should remain in remote caches. Typically, a remote server will only cache those records for the length of time specified by the TTL. After that, the remote server will remove the zone file from its local cache and ask again for an authoritative answer. Due to this, shorter TTLs can cause heavier loads on an authoritative nameserver.
Tags: lower, plesk, TTL, value
How to set up one domain to be your DNS in Plesk
You must first have the domain you wish to make your DNS already set up in Plesk. You will also need at least 2 IP’s to use for your server. For reference, in this article ’serverbuddies.com’ will refer to the domain name you are using. Make sure to replace this with your actual domain name.
1. Log into your Plesk control panel as Administrator and select the domain from the Domains list you wish to make DNS.
2. Select the DNS icon from your services list.
3. Select the link serverbuddies.com from the Host list, with Record Type NS and Value ns.serverbuddies.com
4. In the Enter nameserver field change the ns.serverbuddies.com to ns1.serverbuddies.com and select OK.
5. From the Tools area select Add Record. For Record type select NS and enter ns2.serverbuddies.com in the Enter nameserver field and select OK.
6. Select from your host list ns.serverbuddies.com with Record type A and change the value to ns1 and select OK.
7. From the Tools area select Add Record again. For Record type leave as A, in the Enter domain name add ns2, in the Enter IP address enter your second IP address that you are going to use and select OK.
8. You should now have 2 Record types with the NS value of ns1.serverbuddies.com and ns2.serverbuddies.com and under the Host list you will also have ns1.serverbuddies.com and ns2.serverbuddies.com with the Record type of A and they will have 2 separate IP’s.
In order to have these added as DNS values for when you add new domains you will need to change the default DNS record in Plesk.
1. Select Server from the list on your left.
2. Select the DNS icon from the Services list.
3. From the Host list select with record type NS and enter ns1.serverbuddies.com in the Enter nameserver field and select OK.
4. From the Tools area select Add New Record. Change the Record type to NS and in the Enter nameserver field input ns2.serverbuddies.com and select OK.
If you want to use 2 separate domains for your DNS this is even easier, because Plesk has already created this for you. You must have 2 domains entered in Plesk and assigned separate IP’s. You would then only need to create a DNS zone template the same way described earlier, only inputting ns1.serverbuddies.com and ns2.serverbuddies.com for your default values.
Reference: http://parallels.com/
Tags: DNS, Domain, one, plesk, Set, up
fsck - check and repair a Linux file system
fsck - check and repair a Linux file system
fsck is used to check and optionally repair one or more Linux file systems. filesys can be a device name (e.g. /dev/hdc1, /dev/sdb2), a mount point (e.g. /, /usr, /home), or an ext2 label or UUID specifier (e.g. UUID=8868abf6-88c5-4a83-98b8-bfc24057f7bd or LABEL=root). Normally, the fsck program will try to handle filesystems on different physical disk drives in parallel to reduce the total amount of time needed to check all of the filesystems.
If no filesystems are specified on the command line, and the -A option is not specified, fsck will default to checking filesystems in /etc/fstab serially.
This is equivalent to the -As options.
The exit code returned by fsck is the sum of the following conditions:
0 - No errors
1 - File system errors corrected
2 - System should be rebooted
4 - File system errors left uncorrected
8 - Operational error
16 - Usage or syntax error
32 - Fsck canceled by user request
128 - Shared library error
The exit code returned when multiple file systems are checked is the bit-wise OR of the exit codes for each file system that is checked.
Tags: check, file, Fsck, linux, repair, System
BIND Security
BIND supports a number of different methods to protect the updating and transfer of zones, on both master and slave nameservers:
DNSSEC — Short for DNS SECurity, this feature allows for zones to be cryptographically signed with a zone key.
In this way, the information about a specific zone can be verified as coming from a nameserver that has signed it with a particular private key, as long as the recipient has that nameserver’s public key.
BINDversion 9 also supports the SIG(0) public/private key method of message authentication.
TSIG — Short for Transaction SIGnatures, a shared secret key exists on the master and slave server, verifying that a transfer from master to slave is authorized.
This feature strengthens the standard IP address-based method of transfer authorization. An attacker would not only need to have access to the IP address to transfer the zone, but they would also need to know the secret key.
BINDversion 9 also support TKEY, which is another shared secret key method of authorizing zone transfers.
Tags: BIND, Security
