> 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.

zfs-discuss mailing list

Reply via email to