Yes there is. Does it make sense (Probably it does :) somehow) ? Because I thought that the same should happen for the Host A. -----Original Message----- From: redhat-list-bounces@xxxxxxxxxx [mailto:redhat-list-bounces@xxxxxxxxxx] On Behalf Of Tom Callahan Sent: Wednesday, February 01, 2006 4:56 PM To: General Red Hat Linux discussion list Subject: Re: linux vs SAN Do you have two physical machines that can see these disks? You referred to HOST B, is there a HOST A, that is presented the same storage as well? Thanks, Tom Callahan TESSCO Technologies Desk: (410)-229-1361 Cell: (443)-506-6216 Email: callahant@xxxxxxxxxx A real engineer only resorts to documentation when the keyboard dents on the forehead get too noticeable. baran.yurdagul@xxxxxxxxxxxxxxx wrote: >Hi Tom, >Thank you very much for the detail, it is really quite usefull but in >our situation there are strange things happening. Just 10 minmutes ago >when I type fdsik -l from Host B I have seen that 2 disks are active >because the other disks cannot be read. I have created a partition on >sdd (sdd1) and make fs and label it. Afterwards I typed fdisk -l again >to see the second active disk but I have been suprized that 4 disks seem >to be accessiable now.. >Isn't it strange ? >Ps. :Do you have some documents ? > >-----Original Message----- >From: redhat-list-bounces@xxxxxxxxxx >[mailto:redhat-list-bounces@xxxxxxxxxx] On Behalf Of Tom Callahan >Sent: Wednesday, February 01, 2006 3:46 PM >To: General Red Hat Linux discussion list >Subject: Re: linux vs SAN > >Welcome to Linux vs. the SAN. It's sometimes a tough road, but it's >wonderful once it's working. > >We currently have several RHEL3 and RHEL4 systems booting and running >exclusively off our SAN's, with no internal storage. We use Qlogic 2340 >HBA's, 2 in each system for High Availability. Our setups utilize two >SAN cabinets, with MD software mirroring between the two SANs. > >Linux has multiple ways of dealing with the Active/Passive pathing >issues of seeing 4 disks, when only two are presented. We currently use >Qlogic's drivers which include "failover" support, this way the driver >loads and all "passive" devices are not presented to the OS, only the >actives. The card handles the occurrence of a path failure, and fails to >the passive path, without the OS ever knowing (short of some entries in >/var/log/messages). > >Multipathing is another option, but I am unsure of support in RHEL 2.1. >There are tons of documents around the net on how to setup multipathing, >including redhat's own documentation in their knowledgebase. > >Behavior you should see in an Active/Passive setup is below: >1 - You have 2 disks presented from the SAN, one 10Gig and one 20Gig >2 - Upon boot, you should see /dev/sda as 10Gig, /dev/sdb as 20Gig, >/dev/sdc as 10Gig, and /dev/sdd as 20Gig (this could be reversed, with >the 20Gig disk showing up first. it depends on the LUNs you have >assigned the disks.) >3 - if you `fdisk -l` each disk, you "should" have two disks come up >with "unable to read from /dev/sdx", those are the passive disks. >4 - When you are formatting/partitioning the disks, you will want to use >the set of disks (set being /dev/sda,b and /dev/sdc,d) that you have >determined are on the active controller path. >5 - Make sure that when you format a disk, you are prepending a Label >onto the disk(mkfs.ext3 -L/labelyouchose /dev/sdx or e2label /dev/sdx >"/labelyouchose"), and use that Label for mounting in /etc/fstab >(LABEL=/labelyouchose /mountpoint ext3 defaults 0 0) > >Again, without a multipathing or failover mechanism, things get very >tricky when determining disks to use. I suggest using one of the above >options, or if multipathing is not available, to upgrade to a newer >release of RHEL. > >Thanks, > >Tom Callahan >TESSCO Technologies >Desk: (410)-229-1361 >Cell: (443)-506-6216 >Email: callahant@xxxxxxxxxx > >A real engineer only resorts to documentation when the keyboard dents on >the forehead get too noticeable. > > > >baran.yurdagul@xxxxxxxxxxxxxxx wrote: > > > >>Hi All, >> >> >> >>I have connected my linux box to Hitachi SAN with 2 HBA. I have two >>nodes and I want to use Veritas as cluster sw. When I wanted to make >>partitioning and create filesystem on the disks I get a bit confused. >>Because of 2 HBA, I have seen 4 disks (Infact I have two). I have >>created a partition and make mkfs.ext3 on to it. But after mkfs.ext3 It >>is strange that partitionin info has been flushed. Did you experience >>such problem before or is there any documentation or howto etc ?? >> >> >> >>BR, >> >> >> >> >> >>********************************************************************** * >> >> >* > > >>Bu elektronik posta ve onunla iletilen butun dosyalar sadece >> >> >gondericisi tarafindan almasi amaclanan yetkili gercek ya da tuzel >kisinin kullanimi icindir. Eger soz konusu yetkili alici degilseniz bu >elektronik postanin icerigini aciklamaniz, kopyalamaniz, yonlendirmeniz >ve kullanmaniz kesinlikle yasaktir ve bu elektronik postayi derhal >silmeniz gerekmektedir. > > >>TURKCELL bu mesajin icerdigi bilgilerin dogrulugu veya eksiksiz oldugu >> >> >konusunda herhangi bir garanti vermemektedir. Bu nedenle bu bilgilerin >ne sekilde olursa olsun iceriginden, iletilmesinden, alinmasindan ve >saklanmasindan sorumlu degildir. 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