Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
Alex wrote: > On Tuesday 12 August 2008 12:52, you wrote: > >> Alex wrote: >> >>> Hello experts, >>> >>> I read that raid software on linux is not cluster aware, so i'm trying to >>> find a solution to join together more computers to form a shared file >>> system and build a SAN (correctly if i am wrong), avoiding usage of raid >>> software. >>> >>> Let say that I have: >>> - N computers (N>8) sharing their volumes (volX, where X=N). Each volX is >>> arround 120GB. >>> - M servers (M>3) - which are accessing a GFS volume (read/write) >>> - Other regular computers which are available if required. >>> >>> Now, I want: >>> - to build somehow a GFS on top of vol1, vol2, ... volN volumes with high >>> data availability and without a single point of failure. >>> >> If You want to use GFS, You would need one volX exported via iSCSI or >> GNDB to M servers. >> > > This exactly what i have now on one of M servers: > [root at rhclm ~]# lsscsi > [0:0:0:0] disk IET VIRTUAL-DISK 0 /dev/sda > [1:0:0:0] disk IET VIRTUAL-DISK 0 /dev/sdb > [root at rhclm ~]# > > here, sda and sdb are block devices imported via iscsi from computer1 and > computer2. > > Question: is possible to group sda and sdb using raid1 software in an array > (/dev/md0) and after that, on top of md0 to create a logical volume and run > GFS? > > AFAIK THIS DESIGN IS IMPOSSIBLE because raid software on linux is NOT > CLUTER-AWARE? So, just using iscsi (or gnbd) to export volX is NOT ENOUGH > because if i am loosing one computerX i am loosing all data on GFS! Right? > > here is the answer http://www.redhat.com/magazine/009jul05/departments/tips_tricks/ >> For HA you could use DRBD - two volumes vol1, vol2 >> created as /dev/drbd0 and exported to M servers. >> > > yes, thats why i want to use drbd, to replace raid1 limitations and group > computerX two by two. In this scenario, remain just one question: how can i > join together /dev/drbd*, or....if this thing is not possible, the question > is: how can i join together all 8 volX in order to have: > - Fault-tolerance: Failure of a single drive (volX) or server (computerX) > should not bring down the GFS! > This isn't the limit of GFS. You can't use DRBD with iSCSI or GNBD because DRBD support only two nodes and You have eight. GFS need shared storage(SAN) - one raw device which could be visible on the few nodes. > >> Your solution isn't good for GFS fs. >> > > i am looking to find it, that's why i'm here... can you suggest me one? > > I can't help You because I did tested any of them ;( >> You can also use other HA/Cluster fs like: hadoop, gluster, kosmos-fs, >> mogile and much more. >> > > I read about lustre (from SUN Microsistems). It seems that is well supported > on linux (centos5/rhel5) and has support for raid/lvm/iscsi, is scaling well > and is easy to extend. Is that correct? Using lustre can i join all volX > (exported via iscsi) toghether in one bigger volume (using raid/lvm) and have > a SHARED STORAGE? > I think You are right. Best Regards Maciej Bogucki