Thread: Question regarding the file system
Hi guys,
I have been given a dual PIII with 768MB RAM and I am going to install
PostgreSQL on it, for data warehousing reasons. I have also been given four
160 Ultra SCSI disks (36MB each) with a RAID controller (Adaptec 2100). I
am going to use a RAID5 architecture (this gives me approximately 103 GB of
data) and install a Debian Linux on it: this machine will be dedicated
exclusively to PostgreSQL.
I was wondering which file system you suggest me: ext3 or reiserfs?
Also, I was thinking of using the 2.6.x kernel which offers a faster thread
support: will PostgreSQL gain anything from it or should I stick with 2.4.x?
Thank you very much,
-Gabriele
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Gabriele, > I have been given a dual PIII with 768MB RAM and I am going to install > PostgreSQL on it, for data warehousing reasons. I have also been given four > 160 Ultra SCSI disks (36MB each) with a RAID controller (Adaptec 2100). I > am going to use a RAID5 architecture (this gives me approximately 103 GB of > data) and install a Debian Linux on it: this machine will be dedicated > exclusively to PostgreSQL. FWIW, RAID5 with < 5 disks is probably the worst-performing disk setup for PG with most kinds of DB applications. However, with 4 disks you don't have a lot of other geometries available. If the database will fit on one disk, I might suggest doing RAID 1 for 2 of the disks, and having two single disks, one with the OS and swap, and one with the database log. If you're doing Debian, make sure to get a current version of PG from Debian Unstable. > I was wondering which file system you suggest me: ext3 or reiserfs? These seem to be equivalent in data=writeback mode for most database applications. Use whichever you find easier to install & maintain. > Also, I was thinking of using the 2.6.x kernel which offers a faster thread > support: will PostgreSQL gain anything from it or should I stick with > 2.4.x? PostgreSQL won't gain anything from the thread support (unless you're using a threaded front-end app with thread-safe ecpg). But it will gain from several other improvements in 2.6, especially better scheduling and VM support. Use 2.6. -- Josh Berkus Aglio Database Solutions San Francisco
Gabriele, > By any chance, do you have some reference or some tests that talk about the > fact that RAID5 with less than 5 disks is not performing? Just this list. But it's easy to test yourself; run bonnie++ and compare the performance of seeks and random writes (which PG does a lot of) vs. a plain single disk. -- --Josh Josh Berkus Aglio Database Solutions San Francisco