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We're considering building an Oracle database with 12 Intel X25-M G2 160GB drives in software RAID10. It'd be running Linux. Database gets some very heavy write activity during the early morning data load, other than that it is mostly read-only (and the read load is fairly minimal).

We're currently running on 11 150GB Velociraptors (also Linux software RAID10), and are hoping the X25-M will speed up the data load.

We currently have redo on different disks than the rest of the data.

I'm wondering a few things:

  1. Any experience with using X25-M drives for databases? The X25-E are unfortunately beyond our budget.
  2. Would it hurt to separate redo off to some magnetic (non-SSD) drives, say 2 (raid1) or 4 (raid10) Seagate Constellations?
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serverfault.com/questions/229833/… -- If you don't mind some downtime you might chance the X25-M.... I think you are playing with fire though. –  Kyle Brandt Mar 3 '11 at 22:55
    
Oracle sells flash products to speed up their database in their servers. oracle.com/us/products/servers-storage/storage/flash-storage/… –  Brian Mar 3 '11 at 23:03
    
@Kyle Brandt: Curious about why you'd expect it to cause downtime, especially in RAID10? I don't see anything in the other question to suggest that. –  derobert Mar 3 '11 at 23:46
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@derobert: I don't have any solid evidence, but I think the write wear in RAID would happen at about the same rate for a mirrored pair. So when one fails the other might fail at about the same time. –  Kyle Brandt Mar 3 '11 at 23:57
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@Kyle Brandt: If you're getting higher figures it's because of caching. The IOPS a disk can provide is determined by the latency and seek time. The IOPS an array can provide is determined by the number of disks, IOPS per disk, read/write mix, and RAID penalty. A good overview is cmdln.org/2010/04/22/analyzing-io-performance-in-linux , and a good calculator is wmarow.com/strcalc –  sciurus Mar 4 '11 at 20:05

3 Answers 3

up vote 1 down vote accepted

I don't have any solid evidence, but I think the write wear in RAID would happen at about the same rate for a mirrored pair. So when one fails the other might fail at about the same time. Therefor I personally have concerns with consumer level SSD in production servers unless you can tolerate some down time and maybe some data loss.

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According to Intel (but this site broke it down easier to read, and was faster to google) writing 100GB of data to the 80GB model of the X25-M drive, it will have a life of 5 years. How many write cycles also depends on how much of the drive is full (for wear leveling and write space)

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No experience, but worth checking out the flash cache posts here. There is more stuff on SSD on his blog, such as here

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A warning about flash cache: it's only supported on Oracle's linux distribution, not on Red Hat or CentOS. –  sciurus Mar 4 '11 at 1:03

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