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Apparently, though unproven, at 18:58 on Wednesday 25 May 2011, Volker Armin |
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Hemmann did opine thusly: |
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> On Wednesday 25 May 2011 10:31:19 Paul Hartman wrote: |
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> > When I move the swap to a slow SD card instead (2MB/sec transfer |
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> > rate), even in that slow device, swapoff on the eMMC swap partition |
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> > with ~500M in-use takes about 2 or 3 minutes at most with the data |
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> > being swapped slowly into the SD card. |
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> > |
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> > So I think in your case it should be much faster than that! |
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> |
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> you are comparing apples with oranges (harddisks with moving arms with |
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> solid state devices). |
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> |
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> Do yourself a favour. Look up how long a harddisk needs to position its |
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> head. |
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> |
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> Now you can calculate how many times a second a harddisk can position its |
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> head. |
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> |
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> Now remember: swap is stupid, so lots and lots of head movement needed (and |
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> a cash flush is running too - so even more movements to write all that |
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> crap to disk), |
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> |
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> The result: the whole mess is fscking slow. |
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> |
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> You can have a nice fat raid with nice and fast harddisks - if you try to |
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> stream to a 15 year old DLT drive with 5/10mb/sec speed the dlt drive will |
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> constantly rewind - because harddisks suck when they have to seek. And swap |
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> (just like a backup) = lots and lots and lots of seeks. |
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That reminds me of how SSDs ought to be much faster than hard disks. |
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But every time I use my Acer netbook (8G SSD) I curse and swear and commit |
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random acts of violence - that first gen SSD controller is the worst possible |
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thing to ever hit computers. I swear the 4G SDHC expansion card is leaps |
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faster.... |
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(completely OT, I know. I'll keep quiet now.) |
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-- |
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alan dot mckinnon at gmail dot com |
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