[Richard Elling] wrote: > Don Enrique wrote: >> Hi, >> >> I am looking for some best practice advice on a project that i am working on. >> >> We are looking at migrating ~40TB backup data to ZFS, with an annual data >> growth of >> 20-25%. >> >> Now, my initial plan was to create one large pool comprised of X RAIDZ-2 >> vdevs ( 7 + 2 ) >> with one hotspare per 10 drives and just continue to expand that pool as >> needed. >> >> Between calculating the MTTDL and performance models i was hit by a rather >> scary thought. >> >> A pool comprised of X vdevs is no more resilient to data loss than the >> weakest vdev since loss >> of a vdev would render the entire pool unusable. >> > > Yes, but a raidz2 vdev using enterprise class disks is very reliable.
That's nice to hear. >> This means that i potentially could loose 40TB+ of data if three disks >> within the same RAIDZ-2 >> vdev should die before the resilvering of at least one disk is complete. >> Since most disks >> will be filled i do expect rather long resilvering times. >> >> We are using 750 GB Seagate (Enterprise Grade) SATA disks for this project >> with as much hardware >> redundancy as we can get ( multiple controllers, dual cabeling, I/O >> multipathing, redundant PSUs, >> etc.) >> > > nit: SATA disks are single port, so you would need a SAS implementation > to get multipathing to the disks. This will not significantly impact the > overall availability of the data, however. I did an availability > analysis of > thumper to show this. > http://blogs.sun.com/relling/entry/zfs_raid_recommendations_space_vs Yeah, I read your blog. Very informative indeed. I am using SAS HBA cards and SAS enclosures with SATA disks so I should be fine. >> I could use multiple pools but that would make data management harder which >> in it self is a lengthy >> process in our shop. >> >> The MTTDL figures seem OK so how much should i need to worry ? Anyone having >> experience from >> this kind of setup ? >> > > I think your design is reasonable. We'd need to know the exact > hardware details to be able to make more specific recommendations. > -- richard Well, my choice of hardware is kind of limited by 2 things : 1. We are a 100% Dell shop. 2. We already have lots of enclosures that i would like to reuse for my project. The HBA cards are SAS 5/E (LSI SAS1068 chipset) cards, the enclosures are Dell MD1000 diskarrays. > -- Med venlig hilsen / Best Regards Henrik Johansen [EMAIL PROTECTED] _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
