Hi
Prashant Desai wrote:
Hi all
i am newbiew to filer and storage , i am eager to know following things but unfortunately m not been able to get the rite pointers which can describe the stuffs in detail
- How exactly the Fiber Channel works ?
what are the stuffs involves in setting up a SAN using a Fiber Channel and what are their functions in details along with the alternative devices that too supports the same functions and can be used
SAN is a bunch of knowing, you can't just learn it on a mailing list i can say the following : disks are behind a network (a SAN network) made by Switch and cables (FC technology) client machines can access to all or a part of those disks protocol going on switch and cables are not ethernet but FC (block access mode - near SCSI protocol) you can partition your disks (i call that your FC storage) in order to reserve such amount for such client You have to keep in mind that a SAN storage project must rely on a single brand of material : don't think about mixing brocade switch with 3com switch or you could go into trouble
the pertinent alternative is to use iSCSI - cheeper because you don't use FC technology but ethernet - independant : you can mix cisco swith with 3com swith with no worry - easier because you already know ethernet technology and don't have to learn FC
the only bad point is the throughput still limited to 1G for iSCSI (ethernet limitation) while FC can still go up to 2G (this situation is supposed to change in the near futur : 10G on ethernet)
- what is the purpose of space reservation as far as Netapp's Filer FCP
support is concern , why people need space reservation for volumes,qtrees or for luns ?
when you create a LUN on a Filer of a certain size, the LUN is not created right of this size but just recorded as having this size if you put some files on the LUN, it will effectively grow until the size you preseted Space reservation is the mechanism to really make the LUN at the size you preseted, at the LUN creation Also, if you intend to use snapshots with the LUN, you have to reserve about 20% more than the size of the LUN (if you LUN is 1000M, you will reserve an overall storage of 2200M = 1000 + 1000 x 1.20). Note that some only use the double : 2TB for a 1TB LUN, you must understand that this depend on snapshot (if you want to write new data in the LUN, but the snapshot can't record the to-be-overwritten data because snapshots are full, the Filer will refuse to write data chages, this will rise a File system Full error, and this is not recommended on LUN, that's why, depending of you snapshot policy and the data change rate on your LUN you can set up different size)
- what size of volume i need to have if i want 1 TB of lun ? i have read
in docs that i should i have atleast 2-3 times volume size if i wanna have lun on the volume that is for 1 TB of lun i need to have 2-3 TB of volume , where the other storage space being used ?
it depends on the need you have of snapshot, if you don't need snapshot, you can design a 1TB LUN in an approx 1TB volume if you need snapshot, you have to study the way data change on the LUN if you can be sure that 20% of the LUN change between two extreme snapshots, design 1TB LUN in a 2.2TB volume
- what would be the usable lun storage capacity if i create lun of 1 TB
? how much space will get utilized for partition table and keeping file systems metadata ?
in a volume, aprox 10% is reserved for the filesystem WAFL so in a raw 1TB volume, you can use up to 900GB for the LUN, the LUN wizard could help you finding the max size (check the wizard with the FilerView : point you browser at http://you_filer/na_admin)
- is it possible to install more then one HBA's on hosts like solaris ,
windows mechines ?
Sure you can but remember, one LUN should be accessed by only one machine at a time
hth
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