similar to: Traffic shaping on CentOS

I've been using tc/htb for network control previously to control bandwidth available to different services running on their own IPs on a unvirtualized host. Now, I have put them into their own guest VM. I would like to be able to do something similar to ensure the more crucial service gets more bandwidth as well as ensuring ssh always get reserved bandwidth. However, when I try the good old

Hi All, I read the advanced networking howto and find a useful way to shape my adsl link. is says: "tc qdisc add dev ppp0 root tbf rate 220kbit latency 50ms burst 1500 [...] Change 220kbit to your uplinks *actual* speed, minus a few percent. If you have a really fast modem, raise ''burst'' a bit. " My adsl''s upload brandwidth is about 120 kbits/sec,

I was having problems with the same server locking up to the point I can't even get in via SSH. I've already used HTB/TC to reserve bandwidth for my SSH port but the problem now isn't an attack on the bandwidth. So I'm trying to figure out if there's a way to ensure that SSH is given cpu and i/o priority. However, so far reading seems to imply that it's probably not going

I've been reading that it's possible to set up a system with multiple NIC to provide redundant internet connectivity such that it will switch to a secondary connection if the primary ISP fails. Is it possible in a similar way to setup redundant LAN routing? I read that it is possible to aggregate/bond multiple NIC to stackable switches that support link aggregation and redundancy. But if

I'm trying to figure out what's causing an average system load of 3+ to 5+ on an Intel quad core. The server has with 2 KVM guests (assigned 1 core and 2 cores) that's lightly loaded (0.1~0.4) each. Both guest/host are running 64bit CentOS 5.6 Originally I suspected maybe it's i/o but on checking, there is very little i/o wait % as well. Plenty of free disk space available on all

I'm trying to resolve an I/O problem on a CentOS 5.6 server. The process basically scans through Maildirs, checking for space usage and quota. Because there are hundred odd user folders and several 10s of thousands of small files, this sends the I/O wait % way high. The server hits a very high load level and stops responding to other requests until the crawl is done. I am wondering if I add

I was trying to do some performance testing between using iSCSI on the host as a diskfile to a guest vs the VM guest using the iSCSI device directly. However, in the process of trying to establish a baseline performance figure, I started increasing the MTU settings on the PCI-express NICs with RTL8168B chips. First bottleneck was discovering the max MTU allowed on these is 7K instead of 9K but

In a moment of epic stupidity, having ran out of space on the root partition of a server due to /var chewing up the space, I added a separate drive for the purpose of mounting it as /var To do so, I mounted the new drive as /var2, cp -R (in hindsight should had rsync to preserve attributes), deleted the original /var to free up space, edited fstab and rebooted... unsurprisingly to a fubar'd

Might be slightly OT as it isn't necessarily a CentOS related issue. I've been using WD Reds as mdraid components which worked pretty well for non-IOPS intensive workloads. However, the latest C7 server I built, ran into problems with them on on a Intel C236 board (SuperMicro X11SSH) with tons of "ata bus error write fpdma queued". Googling on it threw up old suggestions to

I've got a server that initially was connected to a static WAN connection via eth0. Now I've added a second NIC eth1 connected to a local network switch with the intention of using it as a backup remote access connection via a dynamic ADSL connection. The problem now is getting the IP address of the dynamic ADSL connection. I've written a script that updates another server with the

hi all, my system with kernel 2.4.16 & 2.4.17( RH-7.2) has netfilter-1.2.4, iproute-ss010803, squid, dns with 4 ether cards.i am trying a simple situation where i want to shape traffic all the interfaces. at present iam using netfilter to allow a few ips, using transparent squid & iproute to limit bandwidth. i feel i must give more bandwidth for my local servers for my office &

Has anybody tried or knows if it is possible to create a MD RAID1 device using networked iSCSI devices like those created using OpenFiler? The idea I'm thinking of here is to use two OpenFiler servers with physical drives in RAID 1, to create iSCSI virtual devices and run CentOS guest VMs off the MD RAID 1 device. Since theoretically, this setup would survive both a single physical drive

Howdy all, I posted this message to the netfilter mailing-list and didn''t get much response. I apologize if anyone here is getting this for a second time. Anyway, I recently migrated my firewall from a FreeBSD box running ipfilter, ipnat and dummynet to a Gentoo Linux box running netfilter and tc. I have to admit that I''m having problems visualizing tc in my head. So, I was

I'm trying to setup a very small system intended for doing monitoring/logging. It's done on an Intel Atoms in a small box and the idea was to simply run it off a pair of USB flash drives in software RAID 1. Now the problem is that while the 6.2 DVD installer could go through the entire install process, grub will load then just stop at the prompt. The system will work if I use a SATA hard

Which of these would be the recommended virtualization platform for mainly CentOS guest on CentOS host for running a virtualized mail server? From what I've read, objectively it seems that VMWare's still the way to go although I would had like to go with Xen or KVM just as a matter of subjective preference. VMWare's offering seems to have the best support and tools, plus likely the

After successfully getting higher MTU to work on my Realtek NICs, I started testing the impact of higher MTU on file transfers using NFS exported ramdisk to ramdisk. The results were unexpected. The higher the MTU on the sending NIC, the lower the file transfer speed. I tested by using time cp to copy a 1GB file (In case compression might affect the results, so I dd the test file from the CentOS

Is it possible or will there be any problems with using mdraid on top of mdraid? specifically say mdraid 1/5 on top of mdraid multipath. e.g. 4 storage machines exporting iSCSI targets via two different physical network switches then use multipath to create md block devices then use mdraid on these md block devices The purpose being the storage array surviving a physical network switch

Second test after big upgrade.. -- http://www.PowerDNS.com Open source, database driven DNS Software http://netherlabs.nl Open and Closed source services

I've been leaning towards actually deploying gluster in one of my projects for a while and finally a probable candidate project came up. However, researching into the specific use case, it seems that gluster isn't really suitable for load profiles that deal with lots of concurrent small files. e.g. http://www.techforce.com.br/news/linux_blog/glusterfs_tuning_small_files

Hello, while investigating a report from Jan-Piet Mens (resulting in http://wiki.powerdns.com/trac/changeset/3109), we discovered that NSD (both 3.2.15 and 4.0.0b4) compresses labels in RP content. As far as I can see, this is not allowed by RFC3597 section 4 paragraph 1/2. PowerDNS Recursor, like Unbound and BIND, now deals with this as 3597 section 4 paragraph 4 says we SHOULD. Nevertheless,