On Wed, Jun 24 at 15:38, Bob Friesenhahn wrote:
On Wed, 24 Jun 2009, Orvar Korvar wrote:
I thought of exchanging my PCI card with a PCIe card variant instead
to reach higher speeds. PCI-X is legacy. The problem with PCIe cards
is that soon SSD drives will be common. A ZFS raid with SSD would need
maybe PCIe x 16 or so, to reach max band width. The PCIe cards are all
PCIe x 4 or something of today. I need a PCIe x 16 card to make it
future proof for the SSD discs. Maybe the best bet would be to attach a
SSD disc directly to a PCIe slot, to reach max transfer speed? Or wait
for SATA 3? I dont know. I want to wait until SSD
I don't think this is valid thinking because it assumes that write rates
for SSDs are higher than for traditional hard drives. This assumption is
not often correct. Maybe someday.
SSDs offer much lower write latencies (no head seek!) but their bulk
sequential data transfer properties are not yet better than hard drives.
The main purpose for using SSDs with ZFS is to reduce latencies for
synchronous writes required by network file service and databases.
In the "available 5 months ago" category, the Intel X25-E will write
sequentially at ~170MB/s according to the datasheets. That is faster
than most, if not all rotating media today.
Eric D. Mudama
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