> - mirroring l2arc won't gain anything, as it doesn't contain any > information that cannot be rebuilt if a device is lost. Further, if a > device is lost, > the system just uses the remaining devices. So I wouldn't waste any > space mirroring l2arc, I'll just stripe them.
I don't plan to attempt to mirror L2ARC. Even the docs say it's unsupported, so no point of that. > - the purpose of a zil device is to reduce latency. Throughput is > probably not > an issue, especially if you configure your pool so that large writes > go to > the main pool. As 2 devices don't have a lower latency than one, I see > no real point in striping slog devices. My guess was a striped setup could give me 2xIOPS if SLOG is designed to do this. Any idea if it is? > - For slog you need SSD with supercap which are significantly more > expensive than without. I'll try the OCZ Vertex 2 Pro in the next few > days and can > give a report how it performs. For L2ARC cheap MLC SSDs will do. hm... Last I checked those OCZ Vertexes were on the both large and expensive side. What do you pay for a couple of small ones? We'll be installing 48 gigs of memory in this box, but I doubt we'll need more than 4GB SLOG in terms of traffic. > So if I had the chance to buy 4 devices, I'd probably buy 2 different > sets. 2 cheap large L2ARC devices, 2 fast supercapped small ones. The > 2 slog devices > would go into a mirror, the L2ARC devices in a stripe. I'd probably > take the > remaining space of the slog devices into the stripe, too, though this > might affect write performance. Any idea if something like a small, decently priced, supercapped SLC SSD exist? Vennlige hilsener / Best regards roy -- Roy Sigurd Karlsbakk (+47) 97542685 r...@karlsbakk.net http://blogg.karlsbakk.net/ -- I all pedagogikk er det essensielt at pensum presenteres intelligibelt. Det er et elementært imperativ for alle pedagoger å unngå eksessiv anvendelse av idiomer med fremmed opprinnelse. I de fleste tilfeller eksisterer adekvate og relevante synonymer på norsk. _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
