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Having read a number of SSD reviews, in particular, of those made by Crucial (a.k.a Micron), I've come to the conclusion that partitioning an SSD is going to make it slower. Here is the logic:

Those reviews explained that (at least the Crucial SSD's based on Marvel controllers) are essentially a RAID array of memory chips soldered to the board, invisible to the end-user as separate entities. I recall one or more of the reviews explicitly stated that the smaller capacity drive sequential access speeds were lacking because it had only half the number of chips of the larger drive. The slowdown was almost linear according to their testing. Thus, I conclude that when I partition such a drive, only a part of the chips are going to be in the partition, thus I'm going to suffer from the said linear slowdown.

Is the above true for Marvell based Crucials? For other drives such as Samsung-controller based, Sandforce-based, others? I'm particularly interested in the Crucial drives, them being the best bang for the buck right now. I'd be happy to also RAID a couple of those on an X79, but totally unsure about partitioning that either. However, that would be a separate question, and not a part of this one, so I'd like to first firgure out partitioning a single SSD drive.

iksemyonov
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2 Answers2

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You already have an useful answer here: Disadvantages of partitioning an SSD?

According to @RobinHood answer, there are small differences regarding the SSD being Ram based or Nad-flash based devices. You'll only have a minor speed disadvantage (outlined below) in the case of Nand-flash based SSDs:

Ram Based S.S.D.s:

There is absolutely no disadvantage because they are random access!

Nand-flash Based S.S.D.s:

The only disadvantages that come to my mind would be:

  1. Wear leveling won't have as much free space to play with, because write operations will be spread across a smaller space , so you "could", but not necessarily will wear out that part of the drive faster than you would if the whole drive was a single partition unless you will be performing equivalent wear on the additional partitions (eg: a dual boot).
  2. Like hard drives nand-flash S.S.D's are sequential access so any data you write/read from the additional partitions will be farther away than it "might" have been if it were written in a single partition, because people usually leave free space in their partitions. This will increase access times for the data that is stored on the additional partitions.
  3. Less total space increases the likely hood of writing fragmented files, and while the performance impact is small keep in mind that it's generally considered a bad idea to defragement a nand-flash S.S.D. because it will wear down the drive. Of course depending on what filesystem you are using some result in extremely low amounts of fragmentation , because they are designed to write files as a whole whenever possible rather than dump it all over the place to create faster write speeds.
Community
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Naceira
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It makes no sense/logic.

Those reviews explained that (at least the Crucial SSD's based on Marvel controllers) are essentially a RAID array

So it's a bad idea to partition RAID array too? That's new to me.

I recall one or more of the reviews explicitly stated that the smaller capacity drive sequential access speeds were lacking because it had only half the number of chips of the larger drive.

But partitioning doesn't make your drive smaller. It's just a big drive, or big RAID in your word, "shared" by multiple partitions.

Thus, I conclude that when I partition such a drive, only a part of the chips are going to be in the partition

A partitioned RAID-0 doesn't make it a JBOD.

Tom Yan
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