I have been tasked to build a large zpool for a data recording system. Using ZFS on Linux (0.6.4.2), on CentOS 6.5.
- DL380 Gen8
- 80 GB ram
- 2x HP HBA H221
- 2x HP D6000, each with 70x 3TB SAS disks
There are some special circumstances:
- Mirroring is out of the question, we would lack storage. The total required amount of TB needed is pretty much set. Adding D6000 units is not an option.
- There will be 2 of these zpool's in the datacenter, using application level redundancy. Thus the loss of the entire pool is problematic, but not critical. All data will be backed up to tape as well.
- Using HP Accelerator cards is not an option right now (too expensive)
- Using PCIe NVMe cards is not an option, due to being restricted to 2.6.32 kernel.
- Writing performance is not critical, there's a basically a steady stream of writing going on, at perhaps 4 MB/sec.
- Reading performance is useful, but there's not really any hot data set, very random which data could or would be read, depending on need.
- Indexing is very important. There will be about 1.5 million files once the zpool is fully loaded, getting a list of these files should be as fast as possible. Does ARC help here, a lot of RAM?
My plan is to build the zpool as follows:
- 14 VDEV's of 10 disks, RaidZ2.
- Compression on
- Autoreplace on
- atime off
I don't really have any good options for SLOG and L2ARC. Using HP SSD's is not really an option, as they would need to run as single device on hardware Raid0. From what I read on this site, that's asking for trouble.
- More RAM would be nice, sure, but do I really need it?
- Should I expect major issues once the zpool is loaded with 95%+ data. Lesser performance is OK, as stated, the performance requirements are quite low.
- Any other vdev layouts recommended, without lowering the available storage.
- Any special ZFS tuning I should consider? I am at least considering increasing the share of metadata stored in the ARC. To help with indexing speed, make sense?
- Should I expect any issues foregoing the use of L2ARC and SLOG device?
- Any other tips to make the above work, much appreciated!