Discuss

discuss@lists.centos.org

34753 discussions

storage servers crashing, hair being pulled out!
by Gordon McLellan 21 Dec '09

21 Dec '09

I have a trio of servers that like to reboot during high disk / network IO operations. They don't appear to panic, as I have kernel.panic = 0 in sysctl.conf. The syslog just shows normal messages, like samba complaining about browse master and then just syslogd starting up. The machines seem to crash when I'm not near the console, usually when I'm trying to pull data off them to another machine running backups. But, they've also crashed trying to copy data off them to other servers (via iscsi). Also, they have crashed being on the receiving end of data via nfs. Two of the servers are linked using drbd and heartbeat, the third is stand alone. Centos 5.4 x86-64 is the flavor of linux on all of them, pretty much vanilla except for the drbd/iscsi stuff. I want to go after the motherboard manufactorer, since I'm more willing to suspect three mobos in a bad lot than three CPUs, especially since one cpu is completely different than the other two. The other variable is the two machines running drbd have promise raid cards in them. I also have the same raid card in my personal server at home. That server also has a nack of crashing during heavy disk IO to the raid volume. The entire OS doesn't crash, just the raid volume, and the only way to bring it back is a reboot. I'm really at a loss on what to do next... Any suggestions? Gordon The hardware config of the drbd servers: Tyan i3210 ICH9 mobo Intel C2D 7500 cpu 4GB A-Data ram Promise ex8650 raid Supermicro 742TQ-865 chassis (865w psu) 8x 1Tb western digital green power drives The third machine: Tyan i3210 ICH9 mobo Intel C2Q 9400 cpu 8GB Mushkin ram dmraid 5 Antec something or other chassis 550W PC Power and Cooling PSU 7x 250gb seagate 7200's

6 7

RHEL 6 won't support Itanic, will support PowerPC, though
by Timo Schoeler 21 Dec '09

21 Dec '09

Hi list, after some discussion on #IRC on PowerPC I was waiting for some commitment on supported architectures in RHEL 6. As I just learnt, Itanic will be dumped, but there will be a PowerPC release: http://www.theregister.co.uk/2009/12/18/redhat_rhel6_itanium_dead/ Best, Timo (happy PowerPC enthusiast :)

3 3

College student printer for CentOS 5.4 x86_64?
by David McGuffey 21 Dec '09

21 Dec '09

Oldest son came back from college and wants a printer for his Dell laptop. I built it with CentOS 5.3 x86_64 several months ago and will upgrade it to 5.4 The Cannon printer he now has (bought with the laptop and Vista through the university book store), doesn't seem to have linux drivers. I built the machine with Vista and CentOS in dual-boot, so he could manage his iTunes and use the printer under Vista. He does almost all his college work under CentOS. Most of his papers are submitted electronically, but occasionally he has to print one. What would the community recommend? His needs are simple...mostly B&W papers. On rare occasions he needs to print a paper with color photos/graphs embedded. Not looking to spend a lot, just enough to satisfy the requirement. DaveM

12 17

Re: [CentOS] Optimizing CentOS for gigabit firewall
by sadas sadas 21 Dec '09

21 Dec '09

>Some months ago there was discussions about 10 gbit performance with >Linux. Some guys were pushing over 70 Gbit/sec through a single linux >box. 70 Gbit/sec ? Maybe with port aggravation it's possible. Can you give some more info about that guys. To achieve that hight throughput maybe it's necessary to cut most of the OS and the kernel, leaving only the necessary. I'm very interested to read more information about the experiment. regards p.s here you can see 10 Gbit/s experiment http://haproxy.1wt.eu/10g.html

2 1

Inquiry:How to recognize the assigned device for attached usb memory?
by hadi motamedi 21 Dec '09

21 Dec '09

Dear All I have attached usb memory to my CentOS 5.2 server and I want to add it to my /etc/fstab . Can you please let me know how can I recognize it from my"/dev/?" list ? Thank you in advance

1 0

Re: [CentOS] Optimizing CentOS for gigabit firewall
by sadas sadas 21 Dec '09

21 Dec '09

I will explain more deeply. I need to deploy a firewall(s) in front of web server farm because I need to do billing - I will use CentOS with iptables + ipset to store a list if my clients so when client doesn't pay his server's IP is out of the list and he can't access the web server. Second - I know that iptables is very heavy and it's not recommended to use it in gigabit firewall but I don't have a choice as far as I know only ipset works with iptables. I don't know can pf store 500 IPs in one list. Ipset is written for that purpose. I can't find information is there linux or BSD distribution with effective firewall that uses optimized algorithm to store hundreds of IPs and to forward huge traffic. Any idea? regards I'll second damn near everything nate said, and hopefully add a tidbit or two. If you're new to BSD, you may want to consider the pfsense project in the aforementioned active-active configuration. It gives you a nice, intuitive gui to manage your failover firewalls, if you insist on putting a firewall in front of your web servers. Better to secure the box, leave only the ports you need open on the public interfaces, and don't firewall them. Also, I'd strongly consider running your firewalls with no disk at all. A Live CD, CF card or USB Flash to boot off of, remote syslog and one less subsystem (disks) to buy/fail makes for some mighty cheap 1U servers. A single dual-core with core speeds above 3.0Ghz and 4GB of RAM is to pass Gb @ line rate - ethernet overhead. Truth be told, it's already being done on much less than that. You can also load balance your traffic, albiet somewhat primitively with it. If you really want massive throughput, consider toying around with extremely expensive 10G gear, size RAM appropriately, and see how PF performs under multi-processor, high-core speed. but if you're handling over a Gb of traffic and you can't split the application into multiple farms, that's the best move. Akamai, for instance, runs 10G to each rack, each rack has around 20-24 servers, and they run GB to the server. pfsense.org has extensive information about hardware requirements, features, and what you're looking to do. https://calomel.org/network_performance.html is an excellent BSD firewall performance site. One thing to note, you are claiming to want to deploy this as a passive bridge. You cannot do what you want to do running anything in bridge mode. The packets need to route somehow. Get a /29 from your colo provider and ask to have your existing block routed through it once you've tested it. Another option for a seamless failover, is to alias a different range of IP's to the server interfaces, put a /29 and whatever netblock you want to end up being your public IP block on the PFSense hardware. When you're convinced everything's working through rigorous testing, put a test domain up pointing to that block, modify virtualhost entries on the servers to respond to that domain with your production web site, and test some more. Once you're convinced that's working perfectly, make the changes in DNS to point your production domain at the IP's you want, and failover will happen with DNS convergence. Peter On Fri, Dec 18, 2009 at 9:06 AM, nate centos(a)linuxpowered.net > wrote: sadas sadas wrote: > > Hi, > I want to configure CentOS on powerful server with gigabit > adapters as transparent bridge and deploy it in front of server farm. > Can you tell how to optimize the OS for hight packet processing? What > configurations I need to do to achieve very hight speeds and thousands of > packets? iptables makes a TERRIBLE firewall, use pf instead http://www.openbsd.org/faq/pf/index.html Also consider how your going to provide redundancy, if you have a web server farm you want to protect them with at least two firewalls, not one. http://www.openbsd.org/faq/pf/carp.html I haven't used CARP myself but did setup a pair of pf firewalls about 5 years ago in a large network in bridging mode, the layer 3 fault tolerance was provided by OSPF on the core switches, the firewalls were active-active(with pfsync) since they were layer 2 only. Maybe someday linux will fix the overly complex iptables system to something that is more manageable, not holding my breath though. If you want really high speed(say multi GbE) though you'll want/need to go with an appliance based solution. Also since your referring to a web server farm, it is perfectly acceptable to not use firewalls these days, if you have a good load balancer that serves the same role as a firewall in that it only passes traffic that you specifically configure it to pass. Also in high traffic environments the performance of load balancers destroys most firewalls, making investing in a high end firewall a very expensive proposition. I've worked for the better part of the last 10 years with companies who did not have firewalls in front of their web servers for this reason, it didn't make sense $ wise, because the benefit wasn't there, and the added complexity, and performance implications wasn't worth it either. Talk to most load balancing companies and they'll tell you this themselves. nate

7 10

Re: [CentOS] Optimizing CentOS for gigabit firewall
by sadas sadas 21 Dec '09

21 Dec '09

What about NetBSD? I heard that NetBSD has the best network stack out there. Maybe NetBSD with pf is the best choice? >>> I can't find information is there linux or BSD distribution with effective >>> firewall that uses optimized algorithm to store hundreds of IPs and to >>> forward huge traffic. Any idea? >> >> Hundreds? >> >> http://www.openbsd.org/faq/pf/tables.html >> >> "A table is used to hold a group of IPv4 and/or IPv6 addresses. Lookups >> against a table are very fast and consume less memory and processor time >> than lists. For this reason, a table is ideal for holding a large group of >> addresses as the lookup time on a table holding 50,000 addresses is only >> slightly more than for one holding 50 addresses. Tables can be used in the >> following ways: >> >> * source and/or destination address in filter, NAT, and redirection rules. >> * translation address in NAT rules. >> * redirection address in redirection rules. >> * destination address in route-to, reply-to, and dup-to filter rule >> options." >> >> nuff said ? >> >> I love linux, I've been using it for almost 15 years now, I absolutely >> hate iptables(and ipchains, and ipfwadm). By contrast I absolutely >> hate everything about OpenBSD except for pf(which I love, ipfw and >> ipf aren't too bad either, at least for the era), so I use OpenBSD >> for firewalls, and linux for everything else. > >I can back this; during 2009, I deployed a bunch of load balancers >running OpenBSD (using pf, carpd, and relayd). I used to be a super die >hard BSD guy, but through the years and having used/deployed/propagated >NetBSD, then FreeBSD, then OpenBSD, then NetBSD again, I took one of my >usual once-a-year looks at GNU/Linux (this time, it was CentOS, after >having worked with RHEL for some years), I got settled here. > >Long story short: I'd really recommend OpenBSD for your task. iptables >really sucks. I recently deployed some machines running several virtual >instances (however still the cheapest *proven* way to get several IP >stacks in Linux) doing L2 routing, I threw iptables off of that machines >because it just can't handle stuff at that rate. OpenBSD rocks, I even >have a setup running (active-active, load balanced) at about 40Mbps >using Alix boards [0] -- they rock, and they are no way busy. > >OpenBSDs documentation is the best out there, it's documentational >quality is what I really really badly miss in the Linux world. However, >the community is a bunch of (sorry in advance) assholes. But this is >well known throughout the internet, so: You have been warned. Great >product, totally lame vendor. ;) > >Timo > >[0] -- http://pcengines.ch/alix.htm > >> nate >_______________________________________________ >CentOS mailing list >CentOS(a)centos.org >http://lists.centos.org/mailman/listinfo/centos >

9 9

Re: [CentOS] Optimizing CentOS for gigabit firewall
by sadas sadas 21 Dec '09

21 Dec '09

>I've been using Linux (CentOS5) on gigabit firewalls, for thousands of >users. No problems. > >Just make sure ip_conntrack_max is big enough, so you don't run out of >connections. > >There are other things to tune to optimize the performance, but it's >certainly doable with linux+iptables. > >-- Pasi > Would you provide us information about how the firewalls are configured, the hardware, the total bandwidth passing the firewall in each direction and the connections in the busiest hours. regards

1 0

Optimizing CentOS for gigabit firewall
by sadas sadas 21 Dec '09

21 Dec '09

Hi, I want to configure CentOS on powerful server with gigabit adapters as transparent bridge and deploy it in front of server farm. Can you tell how to optimize the OS for hight packet processing? What configurations I need to do to achieve very hight speeds and thousands of packets?

7 6

Re: [CentOS] Optimizing CentOS for gigabit firewall
by sadas sadas 20 Dec '09

20 Dec '09

What solution for gigabit firewall can you suggest? Witch OS and packet filter is capable to atcheave hight performance and gigabit speeds? >Les Mikesell wrote: >> Timo Schoeler wrote: >>>> What about NetBSD? I heard that NetBSD has the best network stack out >>>> there. Maybe NetBSD with pf is the best choice? >>> NetBSD is a very nice OS, I personally like it most (out of all BSDs out >>> there); however, as can be read on >>> >>> http://www.netbsd.org/docs/network/pf.html >>> >>> there's the 'usual lag': OpenBSD implements feature X in 4.6, wait some >>> time to see it implemented elsewhere. >>> >>> One of the biggest strengths of OpenBSD is that it's really a completely >>> rounded piece of work. Keep it that way. pf will perform best on >>> OpenBSD, with all the nice features it has. >> >> Has anyone used Firewall Builder to create a complex set of iptables >> rules? Or compared performance where it built the same thing for >> linux/iptables and bsd/pf? >> > > >Are you joking? That piece of crap just puts everything into one single >chain. I never EVER use Firewall Builder after I saw the results the >first time. > >For a BRIDGING firewall, there is absolutely NO WAY that Linux/netfilter >can keep up with OpenBSD/pf. I doubt that Linux/netfilter can even reach >half the performance of OpenBSD/pf. >_______________________________________________ >CentOS mailing list >CentOS(a)centos.org >http://lists.centos.org/mailman/listinfo/centos >

4 6

Jump to page:

2026

2025

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

Discuss