Subject Re: BLOB Restore Speed
Author andreas_kc
We are using a page size of 16384. Backup speed is pretty good. It takes 3 hours to backup a 60GB database. This includes the time needed to send it over CIFS on gigabit Ethernet.

Restore speed on the other hand is awful. Restores take between 28-36 hours. When observing the machine during a restore, it seems real suspicious that CPU/Drive usage is so low during the two tables we use to store large blobs vs the other tables that stream out fast enough to keep CPU/Drives at 100%. About 25GB out of the 60GB Total comes from these two tables and they take about 75% of the restore time.

Machine Specs

Fedora release 7 (Moonshine) Redhat Tikanga 5
Dell Poweredge Server 1750, Dual P4-Xeon 3.0, 3GB Ram, Direct Attached SCSI U320 RAID10 500GB

It would be great if the restore speed was even twice as long as backup (6 hours), but I could probably live with it around 12-20 hours. I've had a slew of corrupted databases over 4 different machines this year and I am getting very frustrated by that and the downtime required to correct it =(



--- In, "Carrell Alex" <Alex.Carrell@...> wrote:
> I have not seen anyone reply.
> So I wonder what the page size of the database is?
> We have a database for blobs, specifically files around 2-12mb. It was slow reading / writing long ago. I changed the page size from 2048 through to 16384. I played with 8096, but found 16384 to work well, given the Ram restraints I had at the time. Very noticeable change in performance. The change used more disk space but that did not matter.
> Backup restore of these tables ~10gb per year is not v slow. about 2 hours, on a 6 year old machine, xeon 1.8ghz x2 (hypethreaded to 4), 3gb ram. On a moderen machine (double everything), the databases restore in is in =< hour, over fibre channel to a san.
> alex
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