Hello, Short version: Can anyone recommend a *many port* (8 or more) SATA/SAS controller (RAID or otherwise) that will allow *SAFE* use of ZFS, including honoring cache flush commands in the sense of submitting them to the underlying device, that is also *low budget* (suitable for personal use; say in the <= $250 range)?
Long version: I am having difficulty getting reliable information on SATA controllers for use with ZFS (that also work with FreeBSD in this case; though I magine the same problem applies with Solaris). The problem is that most non-RAID controllers do not have enough ports. In fact the only one I have found that is decent is the Supermicro Marvell card; but that is PCI-X rather than PCI (or PCI Express). Works in one machine, doesn't in another (presumably because of PCI-X; only have PCI slots). And even if it does work, you are rather limited in bandwidth. Not that I really care about the latter for low budget use. You might say that just get a RAID controller and configure it for JBOD. Well, I was assuming that would be aafe bet, but apparanly you cannot trust them to behave correctly with respect to write caching and cache flushing. I recently found out that the Dell supplied LSI MegaRaid derived Perc 5/i RAID controllers will not honor cache flush requests (according to Dell technical support, after quite some time trying to explain to them what I wanted to know). So assuming this information is correct (I never saw the actual response from the "behind the lines" tech support that my tech support contact in turn asked), it means that running without battery backup, you actually negate the safety offered by ZFS with respect to write caching, making the pool less reliable than it would be with a cheap non-RAID card. Right now I have noticed that LSI has recently began offering some lower-budget stuff; specifically I am looking at the MegaRAID SAS 8208ELP/XLP, which are very reasonably priced. The problem again is that, while they are cheap raid cards without cache, my understanding is that it is still primarily intended for RAID rather than plain SATA "pass-through". As a result I am worried about the same problem as with the Perc 5/i. Of course, LSI being a large corporation, it is seemingly impossible to obtain contact information for them, or find any technical specifications that would contain information as specific as what it will do in response to cache flush requests, so I am at a loss. Unless you're buying 10 000 cards it's difficult to get answers. Does anyone have suggestions on what to choose, that will actually work the way you want it for JBOD use with ZFS? Or avenus of investigation? Is there any chance of a lowly consumer getting any information out of LSI? Is there some other manufacturer that provide low-budget stuff that you can get some technical information about? Does anyone have some specific knowledge of a suitable product? -- / Peter Schuller PGP userID: 0xE9758B7D or 'Peter Schuller <[EMAIL PROTECTED]>' Key retrieval: Send an E-Mail to [EMAIL PROTECTED] E-Mail: [EMAIL PROTECTED] Web: http://www.scode.org
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