similar to: Couple of questions about ZFS on laptops

Hello all, A few months ago I saw a statement that L2ARC writes are simplistic in nature, and I got the (mis?)understanding that some sort of ring buffer may be in use, like for ZIL. Is this true, and the only metric of write-performance important for L2ARC SSD device is the sequential write bandwidth (and IOPS)? In particular, there are some SD/MMC/CF cards for professional photography and

Hello, Im about to migrate a 6Tb database from Veritas Volume Manager to ZFS, I want to set arc_max parameter so ZFS cant use all my system''s memory, but i dont know how much i should set, do you think 24Gb will be enough for a 6Tb database? obviously the more the better but i cant set too much memory. Have someone implemented succesfully something similar? We ran some test and the

I have some questions about the choice of SSDs to use for ZIL and L2ARC. I''m trying to build an OpenSolaris iSCSI SAN out of a whitebox system, which is intended to be used as a backup SAN during storage migration, so it''s built on a tight budget. The system currently has 4GB RAM, 3GHz Core2-Quad and 8x 500GB WD REII SATA HDDs attached to an Areca 8port ARC-1220 controller

Greeting All I have create a pool that consists oh a hard disk and a ssd as a cache zpool create hdd c11t0d0p3 zpool add hdd cache c8t0d0p0 - cache device I ran an OLTP bench mark to emulate a DMBS One I ran the benchmark, the pool started create the database file on the ssd cache device ??????????? can any one explain why this happening ? is not L2ARC is used to absorb the evicted data

[This email is either empty or too large to be displayed at this time]

Hi, Out of pure curiosity, I was wondering, what would happen if one tries to use a regular 7200RPM (or 10K) drive as slog or L2ARC (or both)? I know these are designed with SSDs in mind, and I know it''s possible to use anything you want as cache. So would ZFS benefit from it? Would it be the same? Would it slow down? I guess it would slow things down, because it would be trying to

Hello all, I understand that relatively high fragmentation is inherent to ZFS due to its COW and possible intermixing of metadata and data blocks (of which metadata path blocks are likely to expire and get freed relatively quickly). I believe it was sometimes implied on this list that such fragmentation for "static" data can be currently combatted only by zfs send-ing existing

Dear ZFS-Users, I want to switch to ZFS, but still want to encrypt my data. Native Encryption for ZFS was added in "ZFS Pool Version Number 30<http://en.wikipedia.org/wiki/ZFS#Release_history>", but I''m using ZFS on FreeBSD with Version 28. My question is how would encfs (fuse encryption) affect zfs specific features like data Integrity and deduplication? Regards

Hi, as Richard Elling wrote earlier: "For more background, low-cost SSDs intended for the boot market are perfect candidates. Take a X-25V @ 40GB and use 15-20 GB for root and the rest for an L2ARC. For small form factor machines or machines with max capacity of 8GB of RAM (a typical home system) this can make a pleasant improvement over a HDD-only implementation." For the upcoming

Hi, my oi151 based home NAS is approaching a frightening "drive space" level. Right now the data volume is a 4*1TB Raid-Z1, 3 1/2" local disks individually connected to an 8 port LSI 6Gbit controller. So I can either exchange the disks one by one with autoexpand, use 2-4 TB disks and be happy. This was my original approach. However I am totally unclear about the 512b vs 4Kb issue.

Dear all Sorry if it''s kind of off-topic for the list but after talking to lots of vendors I''m running out of ideas... We are looking for JBOD systems which (1) hold 20+ 3.3" SATA drives (2) are rack mountable (3) have all the nive hot-swap stuff (4) allow 2 hosts to connect via SAS (4+ lines per host) and see all available drives as disks, no RAID volume. In a

Hi, I''ve ordered a new server with: - 4x600GB Toshiba 10K SAS2 Disks - 2x100GB OCZ DENEVA 2R SYNC eMLC SATA (no expander so I hope no SAS/ SATA problems). Specs: http://www.oczenterprise.com/ssd-products/deneva-2-r-sata-6g-2.5-emlc.html I want to use the 2 OCZ SSDs as mirrored intent log devices, but as the intent log needs quite a small amount of the disks (10GB?), I was wondering

Hello everyone, I''m wondering if the following makes sense: To configure a system for high IOPS, I want to have a zpool of 15K RPM SAS drives. For high IOPS, I believe it is best to let ZFS stripe them, instead of doing a raidz1 across them. Therefore, I would like to mirror the drives for reliability. Now, I''m wondering if I can get away with using a large capacity 7200

I posted a thread on this once long ago[1] -- but we''re still fighting with this problem and I wanted to throw it out here again. All of our hardware is from Silicon Mechanics (SuperMicro chassis and motherboards). Up until now, all of the hardware has had a single 24-disk expander / backplane -- but we recently got one of the new SC847-based models with 24 disks up front and 12 in the

Hi, When deploying ZFS in cluster environment it would be nice to be able to have some SSDs as local drives (not on SAN) and when pool switches over to the other node zfs would pick up the node''s local disk drives as L2ARC. To better clarify what I mean lets assume there is a 2-node cluster with 1sx 2540 disk array. Now lets put 4x SSDs in each node (as internal/local drives). Now

hi, I am planning to replace my old CentOS 6 mail server soon. Most details are quite obvious and do not need to be changed, but the old system was running on spinning discs and this is certainly not the best option for todays mail servers. With spinning discs, HW-RAID6 was the way to go to increase reliability and speed. Today, I get the feeling, that traditional RAID is not the best option for

I have an Intel X25-M 80GB SSD. For optimum performance, I need to block align the SSD device, but I am not sure exactly how I should to it. If I run the format -> fdisk it allows me to partition based on a cylinder, but I don''t think that is sufficient enough. Can someone tell me how they block aligned an SSD device for use in l2arc. Thanks, Geoff

Hello Phil, Wednesday, September 16, 2020, 7:40:24 PM, you wrote: PP> You can achieve this with a hybrid RAID1 by mixing SSDs and HDDs, and PP> marking the HDD members as --write-mostly, meaning most of the reads PP> will come from the faster SSDs retaining much of the speed advantage, PP> but you have the redundancy of both SSDs and HDDs in the array. PP> Read performance is

Hi all I have a test system with snv134 and 8x2TB drives in RAIDz2 and currently no Zil or L2ARC. I noticed the I/O speed to NFS shares on the testpool drops to something hardly usable while scrubbing the pool. How can I address this? Will adding Zil or L2ARC help? Is it possible to tune down scrub''s priority somehow? Best regards roy -- Roy Sigurd Karlsbakk (+47) 97542685 roy at

Hello all, It was often asked and discussed on the list about "how to change rpool HDDs from AHCI to IDE mode" and back, with the modern routine involving reconfiguration of the BIOS, bootup from separate live media, simple import and export of the rpool, and bootup from the rpool. The documented way is to reinstall the OS upon HW changes. Both are inconvenient to say the least.