Hi Shih-Che, If I understand correctly you have three nodes (PC's) with local harddisks of size 35GB. You want to make a raid-5 array using these three harddisks and at the sametime make this data accessible from all the three nodes. Is it correct? I am sorry but I didn't try GNBD myself yet. I don't know how much I can help you. But let me try >#gfs_mkfs -p lock_gulm -t alpha:gfstest -j 3 /dev/pool/storage >#mount -t gfs /dev/pool/storage /gfs1 Instead of making one big pool of 70GB make three pools /dev/pool/storage1,2, 3. and then you can mount them onto /gfs1,2,3. You can then use Linux MD (Meta Devices) driver to create raid-5 array (software raid). You will edit /etc/raidtab, check this link: http://www.tldp.org/HOWTO/Software-RAID-HOWTO-5.html#ss5.8 It's just my thought but I don't know if it works. You may want to post this question and my reply to linux-cluster and see if any experts can help you out. Also, it looks like PVFS (Parallel Virtual File System) may address your problem correctly. Check this: Look at what is PVFS? http://www.parl.clemson.edu/pvfs/pvfs-faq.html#what Hope this helps! Raj On Tue, 30 Nov 2004 Shih-Che Huang wrote : - Hide quoted text - >Hi Raj, > >Following is my idea. >Do you think that I can do it under GNBD? > >I have two nodes and each of them has 35GB, and then I want to combine two >storage together to be 70GB. > >Under this condition, I can use this 70GB storage. > > Master /gfs1 (70 GB) > | > | > / \ > / \ > Kh00 Kh01 > 35GB 35GB > >I import GNDB from Kh00 and Kh01 and then I had following storage.cfg > >poolname stogage >minor subpools 2 >subpool 0 128 1 gfs_data >subpool 1 128 1 gfs_data >pooldevice 0 0 /dev/gnbd/gfstest >pooldevice 1 0 /dev/gnbd/gfstest1 > >======================= >#gfs_mkfs -p lock_gulm -t alpha:gfstest -j 3 /dev/pool/storage >#mount -t gfs /dev/pool/storage /gfs1 > >After I mounted it, I can see 70GB storage and I can used it. > >we also want some >RAID1 or RAID5-like redundancy in case of a hard drive failure. > >So it would be more like this: >We have three nodes, kh00, kh01, kh02, each with 35 GB, that together >give us a 70 GB GFS with 35 GB of parity/redundancy. >It's more likely to be like this: >We have four nodes, kh00, kh01, kh02, kh03, each with 35 GB, that are >paired up in redundant copies, yielding 70 GB of usable storage. > >What should I do by using GNBD in GFS? >Could you give me some suggestion? > >Shih-Che -- Shih-Che Huang
