> From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss-
> boun...@opensolaris.org] On Behalf Of Jim Klimov
> One idea I have is that a laptop which only has a single HDD slot,
> often has SD/MMC cardreader slots. If populated with a card for L2ARC,
> can it be expected to boost the laptop's ZFS performance?
You won't find that type of card with performance that's worth a damn. Worse
yet, it will likely be extremely unreliable.
In a SSD, all the performance and reliability come from intelligence in the
controller, which emulates SATA HDD on one side, and manages Flash memory on
the other side. Things like wear leveling, block mapping, garbage collection,
etc, that's where all the performance comes from. You're not going to get it
in a USB stick or a SD card. You're only going to get it in full size SSD's
that consume power, and to some extent, the good stuff will cost more. (But of
course, there's no way for the consumer to distinguish between paying for
quality, and paying for marketing and margin, without trying it.)
Even if you do try it, most likely you won't know the difference until a month
later, having two identical systems with identical workload side-by-side. This
is NOT to say the difference is insignificant; it's very significant, but
without a point of reference, you don't have any comparison. All the published
performance specs are fudged - but not lies - they represent optimal
conditions, which are unrealistic. All the mfgrs are going to publish
comparable specs, and none of them represent real life usage.
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