On Thu, May 08, 2014 at 07:55:25AM -0400, Steven McDowall via smartos-discuss wrote:
> I am curious as to why having 2 different drives (for SLOG and for L2ARC) is > a good idea? I've been reading the series > > https://pthree.org/2012/12/07/zfs-administration-part-iv-the-adjustable-replacement-cache/ I'd be skeptical of ZFS advice from someone who doesn't know that the ARC is the *adaptive* replacement cache, especially since even Wikipedia knows that. The short answer is that the two workloads are markedly different, and SSDs are designed and marketed for different workloads. You can pretty well buy disk "by the litre" today, but that's not at all the case with SSDs. To the original question, the parts we use at Joyent can always be found at http://eng.joyent.com/manufacturing. Those are the ones with which we have direct experience and in which we have the most confidence. We always recommend using our Certified configurations. Notice that we don't use L2ARC; demand for it in JPC has been limited to nonexistent (I wonder if you're really sure you need it). I should also mention that the Mach16 is EOL and HGST/STEC have not come out with a replacement for it (Keith's pet peeve #464: vendors who EOL good hardware without providing a similar replacement). As such, you may have difficulty sourcing that part. The S840z is a fine substitute for it in the same form factor, and is much faster; however, it's also much more expensive. HGST has unfortunately put me in a situation where I am unable to recommend any of their products for use as a slog in the same price range as the Mach16. Unless they come out with something great later this year, we'll probably be stuck with the DCS3700. > And it seems like how A Toponce does it makes sense : get 2 good quality > (but not necessarily large) SSDs and partition them into 2 areas: one > "fairly" small for the SLOG and the other larger partition for the L2ARC ... > ?? > > In his case he did 5GB for the SLOG and the rest (45GB) for the Cache .. > > Seems like a good use of resources? No, but not only have I already explained why, someone has helpfully quoted me doing so! ------------------------------------------- smartos-discuss Archives: https://www.listbox.com/member/archive/184463/=now RSS Feed: https://www.listbox.com/member/archive/rss/184463/25769125-55cfbc00 Modify Your Subscription: https://www.listbox.com/member/?member_id=25769125&id_secret=25769125-7688e9fb Powered by Listbox: http://www.listbox.com
