On March 14, 2021 3:35:21 PM UTC, Kent Watsen <[email protected]> wrote: >[sending again fro a different account, since last-nights send did’t go >thru] > >I have a ZIL/Slog composed of a mirrored-pair of Intel DC P3700 SSDs, >which have power loss protection (PLP). > >I’m entertaining the idea of obtaining some SSDs for a zpool storing >“hot data” (web, email, etc.) separate from another zpool for “cool >data” (large media files, backups, etc.). I plan to partition the >400GB P3700 and use half for each zpool. > >For the SSDs, there appears to be roughly three categories: > > 1) DRAM-less (e.g., Crucial BX500) > 2) DRAM w/o PLP (e.g., WD Red SA500, SanDisk Ultra 3D) > 3) DRAM w/ PLP (e.g., Synology SAT5200, IronWolf 110) > >Would DRAM-less be best for this application, so that the SSDs don’t >lie to the ZIL about having persisted data to NAND? > >Some might say that category (3) are the best drives, but wouldn’t many >of their features be redundant in this application, and it'd be cheaper >to centralize the PLP-function than having it in each drive the the >zpool? > >Thanks, >Kent >------------------------------------------ >illumos: illumos-discuss >Permalink: >https://illumos.topicbox.com/groups/discuss/T1d25146fb4ce0f44-M8cd6cd8ebfa70456e3b59ab6 >Delivery options: >https://illumos.topicbox.com/groups/discuss/subscription
Just to complete your list, 4. DRAM-only (with PLP) - there are devices that present a RAM disk which can flush out to a flash card/chip on power loss. For ZIL you write (sequentially) a lot and read hopefully never, so wearing the SSD flash is best avoided. Also typically you don't need a large ZIL (depends on main pool write speed ability and real-life intensity), so some 4G are often more than enough. Jim -- Typos courtesy of K-9 Mail on my Android ------------------------------------------ illumos: illumos-discuss Permalink: https://illumos.topicbox.com/groups/discuss/T1d25146fb4ce0f44-Mdef1fdc379937e43cc410517 Delivery options: https://illumos.topicbox.com/groups/discuss/subscription
