On Tue, Feb 7, 2012 at 19:34, Ben Scott <[email protected]> wrote: > On Tue, Feb 7, 2012 at 7:22 PM, Kurt Buff <[email protected]> wrote: >> I've got a new-ish (January) EMC VNXe 3100, and have run into a >> troubling limitation - in use as an iSCSI device, it doesn't support >> LUNs larger than 1.99tb. > > Find out what other ways can you use it (other than iSCSI), and what > the limits are then. That information may be helpful.
It does SAN, but I quite leery about it. I asked the reseller directly about the limitations of their implementation for file/directory path length (I've been stung by that before...), and never got an answer. It does NFS, too - but we have no use for that - we're strictly a Windows shop - except where I can sneak in a FreeBSD box for sysadmin tasks... >> According to a post by EMC staff on their community forum, it's >> doe to the implementation of the SCSI II protocol. > > I've been digging around trying to find a concise, authoritative, > single-location answer to this. Not having much luck satisfying all > of those conditions. > > But if I'm interpreting the SCSI-2 specification correctly, the > biggest command block defined has a 32-bit LBA field. As such, you're > limited to 2^32 blocks of storage. > > Given the typical block size of 512 bytes, that works out to 2^41 > bytes, or exactly 2 TiB. So there may be some validity to what > they're saying. > > Of course, the SCSI-2 specification was published in 1994, almost > twenty years ago, so one has to ask why they're using such an old > document. > > Other block sizes (bigger than 512 bytes) are perfectly acceptable > to SCSI -- even SCSI-2. So one could get larger capacities by > increasing the block size. EMC would have to implement that, of > course. I also don't know if such a block size would be acceptable to > the Windows iSCSI stack. > > Later SCSI specs defined still larger command blocks, with 64-bit LBAs. And, that's part of the reason I asked - if this unit's bigger brethren can handle studly GPT volumes as well as Win2k3 can, then it's truly a bad decision to hold back on it for market differentiation. Kurt ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~ --- To manage subscriptions click here: http://lyris.sunbelt-software.com/read/my_forums/ or send an email to [email protected] with the body: unsubscribe ntsysadmin
