Bob Friesenhahn wrote:
On Thu, 7 May 2009, Scott Lawson wrote:
A STK2540 storage array with this configuration:
* Tray 1: Twelve (12) 146 GB @ 15K SAS HDDs.
* Tray 2: Twelve (12) 1 TB @ 7200 SATA HDDs.
Just thought I would point out that these are hardware backed RAID
arrays. You might be better off using the J4200
instead for this so ZFS can manage the disks completely as well. Will
probably be cheaper too! The savings could
be put towards some SSD's or more system RAM for L1ARC.
Something nice about the STK2540 solution is that if the server system
dies. The STK2540's can quickly be swung over to another system via a
quick 'zfs import'.
Sure provided they have it attached to a fibre channel switch or have a
nice long fibre lead. The difference is negligible
other than cost. Roger replied off list and mentioned customer has the
2540 already, so my suggestion is moot anyway for him.
FYI. I have relocated zpools both ways, with SAN attached 3510, 11's,
6140's and SAS attached J4500's. Both ways work just fine. One
is cheaper. ;) Being that he was mentioning astronomical data, which I
know is large datasets I just thought I would point it out the 2540
probably wouldn't offer the best bang for buck for this NFS server.
Thats all.
If SSDs are embedded inside the server system then it is necessary to
physically move the log devices to the new system.
It is possible to buy these J series JBODS with bundled SSD's as well
right now. Log device would be contained in this
chassis which would facilitate easy importing and exporting in the case
of a system shift being required.
The issue about how to quickly recover after the server dies seems to
rarely be discussed here. Embedded log devices tend to make issues
more complex.
A dumb SAS array is certainly much cheaper and will perform at least
as well, but it does seem like these newfangled embedded log devices
cause an issue when maximum availability is desired. With SAS it is
necessary to physically swing the cables to the replacement server and
of course the replacement server needs to be very close by.
Bob
--
Bob Friesenhahn
bfrie...@simple.dallas.tx.us,
http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/
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