Jonathan Edwards wrote:
Now with thumper - you are SPoF'd on the motherboard and operating system - so you're not really getting the availability aspect from dual controllers .. but given the value - you could easily buy 2 and still come out ahead .. you'd have to work out some sort of timely replication of transactions between the 2 units and deal with failure cases with something like a cluster framework.
No. Shared data clusters require that both nodes have access to the storage. This is not the case for a thumper, where the disks are not dual-ported and there is no direct access to the disks from an external port. Thumper is not a conventional highly-redundant RAID array. Comparing thumper to a SE3510 on a feature-by-feature basis is truly like comparing apples and oranges. As far as SPOFs go, all systems which provide a single view of data have at least one SPOF. Claiming a RAID array does not have a SPOF is denying truth.
Then for multi-initiator cross system access - we're back to either some sort of NFS or CIFS layer or we could always explore target mode drivers and virtualization .. so once again - there could be a compelling argument coming in that arena as well. Now, if you already have a big shared FC infrastructure - throwing dense servers in the middle of it all may not make the most sense yet - but on the flip side, we could be seeing a shrinking market for single attach low cost arrays.
From a space perspective, I can put a TByte on my desktop today. Death of the low-end array is assured by bigger drives.
Lastly (for this discussion anyhow) there's the reliability and quality issues with SATA vs FC drives (bearings, platter materials, tolerances, head skew, etc) .. couple that with the fact that dense systems aren't so great when they fail .. so I guess we're right back to choosing the right systems for the right purposes (ZFS does some great things around failure detection and workaround) .. but i think we've beat that point to death ..
Agree, in principle. However, the protocol used to connect to the host is immaterial to the quality of the device. The market segments determine the quality of the device, and the drive vendors find it in their best interest to keep consumer devices inexpensive at all costs, and achieve higher margins on enterprise class devices. What we've done for thumper is to use a top-of-the-line quality SATA drive. AFAIK today, the vendor is Hitachi, though we like to have multiple sources, if they can meet the specifications. Often the vendor and part information is available on the SunSolve Systems Handbook, http://sunsolve.sun.com/handbook_pub/Systems under the Full Components List selection for the specific system. Today, the Sun Fire X4500 is not listed as it has not reached general availability, yet. Look for it soon. So, what is thumper good for? Clearly, it can store a lot of data in a redundant manner (eg. good for retention). GreenPlum, http://www.greenplum.com is building data warehouses with them. Various people are interested in them for streaming media. We don't really know what else it will be used for, there isn't much to compare against in the market. What we do know is that it won't be appropriate for replacing your SE9985 on your ERP system. -- richard _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
