Re: High availability virtual ip
2009/6/24 Michael Tewner tew...@gmail.com: Hi all - If all you want to do is float an IP, Linux-HA will work, but a simpler solution could be, say, keepalived and vrrpd. Doesn't vrrpd require cooperation from the switch? I you would like to also manage cluster resources, Linux-HA is your best solution. I would agree that it has a steep learning curve, and it's a pain, but it does exactly what you want, and more. It will handle all of your cluster resources - We've used it for MySQL, DRBD, OCFS2, Asterisk, and others. I've been using Linux-HA for about 18 months now. Using the packages bundled with CentOS 5 (started at 5.0 and at 5.3 now). Although the packages are version 2, I couldn't get the fancier version 2 xml style configuration to work, it just kept crashing one of the daemons. So I stick to the older haresources style and it works, but I'm always suspicious about how well it'll behave in real tight corners. I have a suspicion that I can learn a lot more and gain more in regards to redundancy and fail-over but try as I might, after a few weeks of fiddling with the more fancy configuration format even just to serve a simple VIP I had to go back to haresources. This was over a year ago so maybe it improved since? What about RedHat Cluster Suite? It's part of CentOS as well, as far as I'm aware, it's based on Linux-HA, and a worker of mine has good experience with it so I'm thinking of maybe checking it when we have some time to breath again. Does it do anything better? --Amos ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: Linux-HA [Was: High availability virtual ip]
2009/6/24 Oleg Goldshmidt p...@goldshmidt.org: 3) Allow me to take the claims of too steep learning curve with a grain of salt. The last time I recall (a year, maybe less, ago) it took a *competent* person a few hours from never heard of Linux-HA to reading the docs, installing and configuring it, integrating it with a very non-trivial server application, verifying in the lab, demoing live that it works, and being very satisfied the experience. This included IP address HA, uninterrupted client sessions through failover, live replication of configuration changes, contiguous real-time management of a complicated network infrastructure through failover, etc. I wonder - was it with the more advanced stuff or the simpler haresources? haresources is indeed trivial, the other thing just didn't work (CentOS 5, x86_64, xen 3.0.x guests, doing VIP for the simplest test case but haresources is used in production for drbd, databases, http servers, vip's, LVS, monitoring stuff (collectd, monit), and home-grown software). If you have a pointer to GOOD documentation/tutorial about the cib and friends then I'd love to see it. Thanks, --Amos ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: Linux-HA [Was: High availability virtual ip]
2009/6/24 Michael Tewner tew...@gmail.com: I you would like to also manage cluster resources, Linux-HA is your best solution. I would agree that it has a steep learning curve, and it's a pain, but it does exactly what you want, and more. It will handle all of your cluster resources - We've used it for MySQL, DRBD, OCFS2, Asterisk, and others. Since I was the one who mentioned Linux-HA/heartbeat in the first place, I feel compelled to say that 0) I have no affiliation or vested interest in Linux-HA, and I am not going to take the job of its public defender on. 1) I cannot comment on the problems that Itay et al. had since I don't know what they were and don't understand some of the (incomplete) use case descriptions. See item 0 above, thorough investigations can go to the appropriate Linux-HA forums. 2) My experiences with Linux-HA were separated in time by a few years and have always been in the context of HA of quite a bit more than just IP address, including DRBD, etc., for management (i.e., no serious high performance server traffic requirements, no five nines or anything like that, only we need HA of management systems; DRBD integration was a big draw.). It is certainly possible that if one needs only a virtual IP there are other solutions. I mentioned it because I knew that virtual IP was one of the things it did. 3) Allow me to take the claims of too steep learning curve with a grain of salt. The last time I recall (a year, maybe less, ago) it took a *competent* person a few hours from never heard of Linux-HA to reading the docs, installing and configuring it, integrating it with a very non-trivial server application, verifying in the lab, demoing live that it works, and being very satisfied the experience. This included IP address HA, uninterrupted client sessions through failover, live replication of configuration changes, contiguous real-time management of a complicated network infrastructure through failover, etc. -- Oleg Goldshmidt | o...@goldshmidt.org ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: High availability virtual ip
Hi Folks, I would recommend not using Linux-HA for any means. I had very bitter experience with it. It is implemented in a very complicated and hard to debug and configure. It's also very poorly tested. I first didn't believe it myself and thought I was doing something wrong, but after some email exchanges with its developer it became apparent that it fails some very basic scenarios (like switch power-down for instance). Moreover, the linux-ha people themselves will confuse you with which version to use (2.99/2.1.4, heartbeat or pacemaker, etc). If you'd like more detailed explanation, or had different experience, you are more than welcome to email me. Itay On Tue, Jun 16, 2009 at 9:55 PM, Oleg Goldshmidtp...@goldshmidt.org wrote: Marc Volovic marcvolo...@me.com writes: Hi First, the problem is not an IP, but the mac-ip mapping and ARP caching strategies. Second, don't use ping. Third, do use project 'heartbeat' and 'fake'. They provide what you need. Heartbeat is a component of Linux-HA, which is why I pointed to the latter ;-) http://www.linux-ha.org/Heartbeat -- Oleg Goldshmidt | p...@goldshmidt.org ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: High availability virtual ip
On Tue, Jun 23, 2009 at 9:01 AM, Itay Donenhirsch i...@bazoo.org wrote: Hi Folks, I would recommend not using Linux-HA for any means. I had very bitter experience with it. It is implemented in a very complicated and hard to debug and configure. It's also very poorly tested. I first didn't believe it myself and thought I was doing something wrong, but after some email exchanges with its developer it became apparent that it fails some very basic scenarios (like switch power-down for instance). Moreover, the linux-ha people themselves will confuse you with which version to use (2.99/2.1.4, heartbeat or pacemaker, etc). If you'd like more detailed explanation, or had different experience, you are more than welcome to email me. Heartbeat has 2 faces, It can work great or it can fail bitterly. It has a very steep learning curse before something useful begins to happen. cibadmin -Q, crm_attribute are your friends. I agree with Itay, from our experience it is indeed buggy but working. Maxim. Itay On Tue, Jun 16, 2009 at 9:55 PM, Oleg Goldshmidtp...@goldshmidt.org wrote: Marc Volovic marcvolo...@me.com writes: Hi First, the problem is not an IP, but the mac-ip mapping and ARP caching strategies. Second, don't use ping. Third, do use project 'heartbeat' and 'fake'. They provide what you need. Heartbeat is a component of Linux-HA, which is why I pointed to the latter ;-) http://www.linux-ha.org/Heartbeat -- Oleg Goldshmidt | p...@goldshmidt.org ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il -- Cheers, Maxim Veksler Free as in Freedom - Do u GNU ? ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: High availability virtual ip
Hi all - If all you want to do is float an IP, Linux-HA will work, but a simpler solution could be, say, keepalived and vrrpd. I you would like to also manage cluster resources, Linux-HA is your best solution. I would agree that it has a steep learning curve, and it's a pain, but it does exactly what you want, and more. It will handle all of your cluster resources - We've used it for MySQL, DRBD, OCFS2, Asterisk, and others. Other options include virtualMonkey and/or Linux Virtual Server ...But I would NOT agree with Itay's I would recommend not using Linux-HA for any means. Linux-HA is the PROPER open solution to clustering, and just 'cause it's hard to figure out doesn't mean that you should choose a less appropriate product. Check: http://www.ntua.gr/lvsp/Joseph.Mack/HOWTO/LVS-HOWTO.failover.html -Mike On Tue, Jun 23, 2009 at 5:04 PM, Maxim Veksler hq4e...@gmail.com wrote: On Tue, Jun 23, 2009 at 9:01 AM, Itay Donenhirsch i...@bazoo.org wrote: Hi Folks, I would recommend not using Linux-HA for any means. I had very bitter experience with it. It is implemented in a very complicated and hard to debug and configure. It's also very poorly tested. I first didn't believe it myself and thought I was doing something wrong, but after some email exchanges with its developer it became apparent that it fails some very basic scenarios (like switch power-down for instance). Moreover, the linux-ha people themselves will confuse you with which version to use (2.99/2.1.4, heartbeat or pacemaker, etc). If you'd like more detailed explanation, or had different experience, you are more than welcome to email me. Heartbeat has 2 faces, It can work great or it can fail bitterly. It has a very steep learning curse before something useful begins to happen. cibadmin -Q, crm_attribute are your friends. I agree with Itay, from our experience it is indeed buggy but working. Maxim. Itay On Tue, Jun 16, 2009 at 9:55 PM, Oleg Goldshmidtp...@goldshmidt.org wrote: Marc Volovic marcvolo...@me.com writes: Hi First, the problem is not an IP, but the mac-ip mapping and ARP caching strategies. Second, don't use ping. Third, do use project 'heartbeat' and 'fake'. They provide what you need. Heartbeat is a component of Linux-HA, which is why I pointed to the latter ;-) http://www.linux-ha.org/Heartbeat -- Oleg Goldshmidt | p...@goldshmidt.org ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il -- Cheers, Maxim Veksler Free as in Freedom - Do u GNU ? ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: High availability virtual ip
Well, you can not trust an HA system that either works great or fails bitterly :) Someone told me that it was primarily designed for 1+1 systems, but I don't believe it can do this task as well. On Tue, Jun 23, 2009 at 4:04 PM, Maxim Vekslerhq4e...@gmail.com wrote: On Tue, Jun 23, 2009 at 9:01 AM, Itay Donenhirsch i...@bazoo.org wrote: Hi Folks, I would recommend not using Linux-HA for any means. I had very bitter experience with it. It is implemented in a very complicated and hard to debug and configure. It's also very poorly tested. I first didn't believe it myself and thought I was doing something wrong, but after some email exchanges with its developer it became apparent that it fails some very basic scenarios (like switch power-down for instance). Moreover, the linux-ha people themselves will confuse you with which version to use (2.99/2.1.4, heartbeat or pacemaker, etc). If you'd like more detailed explanation, or had different experience, you are more than welcome to email me. Heartbeat has 2 faces, It can work great or it can fail bitterly. It has a very steep learning curse before something useful begins to happen. cibadmin -Q, crm_attribute are your friends. I agree with Itay, from our experience it is indeed buggy but working. Maxim. Itay On Tue, Jun 16, 2009 at 9:55 PM, Oleg Goldshmidtp...@goldshmidt.org wrote: Marc Volovic marcvolo...@me.com writes: Hi First, the problem is not an IP, but the mac-ip mapping and ARP caching strategies. Second, don't use ping. Third, do use project 'heartbeat' and 'fake'. They provide what you need. Heartbeat is a component of Linux-HA, which is why I pointed to the latter ;-) http://www.linux-ha.org/Heartbeat -- Oleg Goldshmidt | p...@goldshmidt.org ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il -- Cheers, Maxim Veksler Free as in Freedom - Do u GNU ? ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: High availability virtual ip
Hi Michael, I wonder - what test scenario did you run on Linux-HA? I tried to used it for floating IPs and cluster resources, it gives the illusion that it works ok but when you start testing it a bit more you see catastrophes. I even submitted a few bugs to their team and one response that I got is oh well, never tested this. That for instance is for switch power down. From my experience, the CRM (if I remember correcly) algorithm is very buggy - it's fun to see the linux-ha segfaults all of the sudden with no apparent reason... Furthermore, what version did you work with? About LVS - it's primarly for load-balancing, using a director server and real servers, I used linux-ha for backup servers (n+1 configuration). Itay On Wed, Jun 24, 2009 at 7:10 AM, Michael Tewnertew...@gmail.com wrote: Hi all - If all you want to do is float an IP, Linux-HA will work, but a simpler solution could be, say, keepalived and vrrpd. I you would like to also manage cluster resources, Linux-HA is your best solution. I would agree that it has a steep learning curve, and it's a pain, but it does exactly what you want, and more. It will handle all of your cluster resources - We've used it for MySQL, DRBD, OCFS2, Asterisk, and others. Other options include virtualMonkey and/or Linux Virtual Server ...But I would NOT agree with Itay's I would recommend not using Linux-HA for any means. Linux-HA is the PROPER open solution to clustering, and just 'cause it's hard to figure out doesn't mean that you should choose a less appropriate product. Check: http://www.ntua.gr/lvsp/Joseph.Mack/HOWTO/LVS-HOWTO.failover.html -Mike On Tue, Jun 23, 2009 at 5:04 PM, Maxim Veksler hq4e...@gmail.com wrote: On Tue, Jun 23, 2009 at 9:01 AM, Itay Donenhirsch i...@bazoo.org wrote: Hi Folks, I would recommend not using Linux-HA for any means. I had very bitter experience with it. It is implemented in a very complicated and hard to debug and configure. It's also very poorly tested. I first didn't believe it myself and thought I was doing something wrong, but after some email exchanges with its developer it became apparent that it fails some very basic scenarios (like switch power-down for instance). Moreover, the linux-ha people themselves will confuse you with which version to use (2.99/2.1.4, heartbeat or pacemaker, etc). If you'd like more detailed explanation, or had different experience, you are more than welcome to email me. Heartbeat has 2 faces, It can work great or it can fail bitterly. It has a very steep learning curse before something useful begins to happen. cibadmin -Q, crm_attribute are your friends. I agree with Itay, from our experience it is indeed buggy but working. Maxim. Itay On Tue, Jun 16, 2009 at 9:55 PM, Oleg Goldshmidtp...@goldshmidt.org wrote: Marc Volovic marcvolo...@me.com writes: Hi First, the problem is not an IP, but the mac-ip mapping and ARP caching strategies. Second, don't use ping. Third, do use project 'heartbeat' and 'fake'. They provide what you need. Heartbeat is a component of Linux-HA, which is why I pointed to the latter ;-) http://www.linux-ha.org/Heartbeat -- Oleg Goldshmidt | p...@goldshmidt.org ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il -- Cheers, Maxim Veksler Free as in Freedom - Do u GNU ? ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: High availability virtual ip
Hi, Linux-HA is one solution, as has been suggested; another, much easier to set up, is UCARP -- http://www.ucarp.org/. It handles your virtual IP and the ARP caching issues associated with it (by means of a GARP packet). I had a good experience with it. --Alex From: Biran, Yahav (Yahav) yahav.bi...@gmail.com To: linux-il@cs.huji.ac.il Sent: Tuesday, June 16, 2009 6:58:02 PM Subject: High availability virtual ip i have two linux machines, that are running on the same LAN. i would like to find a way to set HA IP. i was thinking on creating virtual ip that will ride on the exiting eth. lets say 10.0.0.1 and 10.0.0.2 and the VIP will be 172.16.4.1 both will run an infinite loop of:while (ping 172.16.4.1) do ... once that the while is exiting in one of the hosts it will try to acquire the VIP. there is additional lock mechanism to implement so the two servers will not try to acquire the same VIP concurrently. i would like to know if there is any out of the box sofware that can do this task? yahav ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
RE: High availability virtual ip
Many thanks, from some reasons I managed to install it only on 32 bit. But this is not an issue. I created the following setup. the two hosts are running on actual ips 172.16.4.195 and 172.16.4.191 respectively. The shared ip to be used by the two servers is 172.16.4.242. this ip is available in the LAN that im running the ucarp. I also created the two network scripts to support the vip in /etc/sysconfig/network-scripts/ I simply copy the existing ifcfg-eth0 to ifcfg-eth0:1 as follow: [r...@ilhaisuv01195 network-scripts]# cat ifcfg-eth0 DEVICE=eth0 BOOTPROTO=static BROADCAST=172.16.7.255 HWADDR=86:EE:0E:6A:F6:92 IPADDR=172.16.4.195 NETMASK=255.255.252.0 NETWORK=172.16.4.0 ONBOOT=yes [r...@ilhaisuv01195 network-scripts]# cat ifcfg-eth0:1 DEVICE=eth0:1 BOOTPROTO=static BROADCAST=172.16.7.255 HWADDR=86:EE:0E:6A:F6:92 IPADDR=172.16.4.242 NETMASK=255.255.252.0 NETWORK=172.16.4.0 ONBOOT=no I also tried to executed: /sbin/ifconfig eth0:2 172.16.4.242 netmask 255.255.255.0 on and /sbin/ifconfig eth0:2 172.16.4.242 netmask 255.255.255.0 down The 242 ip was successfully allocated and reallocated. This two command lines were script as required in the readme to /etc/vip-up.sh and /etc/vip-down.sh [r...@ilhaisuv01195 network-scripts]# cat /etc/vip-up.sh #! /bin/sh /sbin/ifconfig eth0:2 172.16.4.242 netmask 255.255.255.0 on [r...@ilhaisuv01195 network-scripts]# cat /etc/vip-down.sh #! /bin/sh /sbin/ifconfig eth0:2 172.16.4.242 netmask 255.255.255.0 down Whe I executing the command: [r...@ilhaisuv01195 network-scripts]# /usr/local/sbin/ucarp --interface=eth0:1 --srcip=172.16.4.195 --addr=172.16.4.242 The following error is generated: [ERROR] You must supply a valid virtual host id Can you please advise what seems to be the problem? yahav From: Alex Shnitman [mailto:alext...@yahoo.com] Sent: Wednesday, June 17, 2009 12:43 PM To: Biran, Yahav (Yahav); linux-il@cs.huji.ac.il Subject: Re: High availability virtual ip Hi, Linux-HA is one solution, as has been suggested; another, much easier to set up, is UCARP -- http://www.ucarp.org/. It handles your virtual IP and the ARP caching issues associated with it (by means of a GARP packet). I had a good experience with it. --Alex From: Biran, Yahav (Yahav) yahav.bi...@gmail.com To: linux-il@cs.huji.ac.il Sent: Tuesday, June 16, 2009 6:58:02 PM Subject: High availability virtual ip i have two linux machines, that are running on the same LAN. i would like to find a way to set HA IP. i was thinking on creating virtual ip that will ride on the exiting eth. lets say 10.0.0.1 and 10.0.0.2 and the VIP will be 172.16.4.1 both will run an infinite loop of:while (ping 172.16.4.1) do ... once that the while is exiting in one of the hosts it will try to acquire the VIP. there is additional lock mechanism to implement so the two servers will not try to acquire the same VIP concurrently. i would like to know if there is any out of the box sofware that can do this task? yahav ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: High availability virtual ip
i used fake and it is working very well, thanks all On 6/16/09, Oleg Goldshmidt p...@goldshmidt.org wrote: Marc Volovic marcvolo...@me.com writes: Hi First, the problem is not an IP, but the mac-ip mapping and ARP caching strategies. Second, don't use ping. Third, do use project 'heartbeat' and 'fake'. They provide what you need. Heartbeat is a component of Linux-HA, which is why I pointed to the latter ;-) http://www.linux-ha.org/Heartbeat -- Oleg Goldshmidt | p...@goldshmidt.org -- Yahav Biran Alcatel-Lucent Multimedia and Ventures 5 Nahum Het Street, 3rd floor Topaz Building, Shaar Hacarmel POB 15049 Haifa 31905, Israel Email: bi...@lucent.com Cell: +972 54 6616208 Phone: +972 4 8138020 Fax: +972 4 8138022 ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
High availability virtual ip
i have two linux machines, that are running on the same LAN. i would like to find a way to set HA IP. i was thinking on creating virtual ip that will ride on the exiting eth. lets say 10.0.0.1 and 10.0.0.2 and the VIP will be 172.16.4.1 both will run an infinite loop of:while (ping 172.16.4.1) do ... once that the while is exiting in one of the hosts it will try to acquire the VIP. there is additional lock mechanism to implement so the two servers will not try to acquire the same VIP concurrently. i would like to know if there is any out of the box sofware that can do this task? yahav ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: High availability virtual ip
2009/6/16 Biran, Yahav (Yahav) yahav.bi...@gmail.com: i have two linux machines, that are running on the same LAN. i would like to find a way to set HA IP. i was thinking on creating virtual ip that will ride on the exiting eth. lets say 10.0.0.1 and 10.0.0.2 and the VIP will be 172.16.4.1 both will run an infinite loop of:while (ping 172.16.4.1) do ... once that the while is exiting in one of the hosts it will try to acquire the VIP. there is additional lock mechanism to implement so the two servers will not try to acquire the same VIP concurrently. i would like to know if there is any out of the box sofware that can do this task? http://www.linux-ha.org/ ? -- Oleg Goldshmidt | o...@goldshmidt.org ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: High availability virtual ip
Hi First, the problem is not an IP, but the mac-ip mapping and ARP caching strategies. Second, don't use ping. Third, do use project 'heartbeat' and 'fake'. They provide what you need. M ---MAV Marc. Volovic +972-54-467-6764 m...@swiftouch.com Sent from my iPhone On Jun 16, 2009, at 6:58 PM, Biran, Yahav (Yahav) yahav.bi...@gmail.com wrote: i have two linux machines, that are running on the same LAN. i would like to find a way to set HA IP. i was thinking on creating virtual ip that will ride on the exiting eth. lets say 10.0.0.1 and 10.0.0.2 and the VIP will be 172.16.4.1 both will run an infinite loop of:while (ping 172.16.4.1) do ... once that the while is exiting in one of the hosts it will try to acquire the VIP. there is additional lock mechanism to implement so the two servers will not try to acquire the same VIP concurrently. i would like to know if there is any out of the box sofware that can do this task? yahav ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: High availability virtual ip
Marc Volovic marcvolo...@me.com writes: Hi First, the problem is not an IP, but the mac-ip mapping and ARP caching strategies. Second, don't use ping. Third, do use project 'heartbeat' and 'fake'. They provide what you need. Heartbeat is a component of Linux-HA, which is why I pointed to the latter ;-) http://www.linux-ha.org/Heartbeat -- Oleg Goldshmidt | p...@goldshmidt.org ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
