255 .ne 2
256 .na
257 \fB\fBmulti_vdev_crash_dump\fR\fR
258 .ad
259 .RS 4n
260 .TS
261 l l .
262 GUID com.joyent:multi_vdev_crash_dump
263 READ\-ONLY COMPATIBLE no
264 DEPENDENCIES none
265 .TE
266
267 This feature allows a dump device to be configured with a pool comprised
268 of multiple vdevs. Those vdevs may be arranged in any mirrored or raidz
269 configuration.
270
271 When the \fBmulti_vdev_crash_dump\fR feature is set to \fBenabled\fR,
272 the administrator can use the \fBdumpadm\fR(1M) command to configure a
273 dump device on a pool comprised of multiple vdevs.
274
275 .SH "SEE ALSO"
276 \fBzpool\fR(1M)
|
255 .ne 2
256 .na
257 \fB\fBmulti_vdev_crash_dump\fR\fR
258 .ad
259 .RS 4n
260 .TS
261 l l .
262 GUID com.joyent:multi_vdev_crash_dump
263 READ\-ONLY COMPATIBLE no
264 DEPENDENCIES none
265 .TE
266
267 This feature allows a dump device to be configured with a pool comprised
268 of multiple vdevs. Those vdevs may be arranged in any mirrored or raidz
269 configuration.
270
271 When the \fBmulti_vdev_crash_dump\fR feature is set to \fBenabled\fR,
272 the administrator can use the \fBdumpadm\fR(1M) command to configure a
273 dump device on a pool comprised of multiple vdevs.
274
275 .RE
276
277 .sp
278 .ne 2
279 .na
280 \fB\fBsha512\fR\fR
281 .ad
282 .RS 4n
283 .TS
284 l l .
285 GUID org.illumos:sha512
286 READ\-ONLY COMPATIBLE no
287 DEPENDENCIES none
288 .TE
289
290 This feature enables the use of the SHA-512/256 truncated hash algorithm
291 (FIPS 180-4) for checksum and dedup. The native 64-bit arithemtic of
292 SHA-512 provides an approximate 50% performance boost over SHA-256 on
293 64-bit hardware and is thus a good minimum-change replacement candidate
294 for systems where hash performance is important, but these systems
295 cannot for whatever reason utilize the faster \fBskein\fR and
296 \fBedonr\fR algorithms.
297
298 When the \fBsha512\fR feature is set to \fBenabled\fR, the administrator
299 can turn on the \fBsha512\fR checksum on any dataset using the
300 \fBzfs\fR(1M) command. Please note that doing so will immediately
301 activate the \fBsha512\fR feature on the underlying pool (even before
302 any data is written). Since this feature is not read-only compatible,
303 this operation will render the pool unimportable on systems without
304 support for the \fBsha512\fR feature. At the moment, this operation
305 cannot be reversed. Booting off of pools utilizing SHA-512/256 is
306 supported, provided that the appropriate GRUB stage2 module is
307 installed.
308
309 .RE
310
311 .sp
312 .ne 2
313 .na
314 \fB\fBskein\fR\fR
315 .ad
316 .RS 4n
317 .TS
318 l l .
319 GUID org.illumos:skein
320 READ\-ONLY COMPATIBLE no
321 DEPENDENCIES none
322 .TE
323
324 This feature enables the use of the Skein hash algorithm for checksum
325 and dedup. Skein is a high-performance secure hash algorithm that was a
326 finalist in the NIST SHA-3 competition. It provides a very high security
327 margin and high performance on 64-bit hardware (80% faster than
328 SHA-256). This implementation also utilizes the new salted checksumming
329 functionality in ZFS, which means that the checksum is pre-seeded with a
330 secret 256-bit random key (stored on the pool) before being fed the data
331 block to be checksummed. Thus the produced checksums are unique to a
332 given pool, preventing hash collision attacks on systems with dedup.
333
334 When the \fBskein\fR feature is set to \fBenabled\fR, the administrator
335 can turn on the \fBskein\fR checksum on any dataset using the
336 \fBzfs\fR(1M) command. Please note that doing so will immediately
337 activate the \fBskein\fR feature on the underlying pool (even before any
338 data is written). Since this feature is not read-only compatible, this
339 operation will render the pool unimportable on systems without support
340 for the \fBskein\fR feature. At the moment, this operation cannot be
341 reversed. Booting off of pools using \fBskein\fR is \fBNOT\fR supported
342 -- any attempt to enable \fBskein\fR on a root pool will fail with an
343 error.
344
345 .RE
346
347 .sp
348 .ne 2
349 .na
350 \fB\fBedonr\fR\fR
351 .ad
352 .RS 4n
353 .TS
354 l l .
355 GUID org.illumos:edonr
356 READ\-ONLY COMPATIBLE no
357 DEPENDENCIES none
358 .TE
359
360 This feature enables the use of the Edon-R hash algorithm for checksum
361 and dedup. Edon-R is a very high-performance hash algorithm that was part
362 of the NIST SHA-3 competition. It provides extremely high hash
363 performance (over 350% faster than SHA-256), but was not selected
364 because of its unsuitability as a general purpose secure hash algorithm.
365 This implementation utilizes the new salted checksumming functionality
366 in ZFS, which means that the checksum is pre-seeded with a secret
367 256-bit random key (stored on the pool) before being fed the data block
368 to be checksummed. Thus the produced checksums are unique to a given
369 pool, blocking hash collision attacks on systems with dedup.
370
371 When the \fBedonr\fR feature is set to \fBenabled\fR, the administrator
372 can turn on the \fBedonr\fR checksum on any dataset using the
373 \fBzfs\fR(1M) command. Please note that doing so will immediately
374 activate the \fBedonr\fR feature on the underlying pool (even before any
375 data is written). Since this feature is not read-only compatible, this
376 operation will render the pool unimportable on systems without support
377 for the \fBedonr\fR feature. At the moment, this operation cannot be
378 reversed. Booting off of pools using \fBedonr\fR is \fBNOT\fR supported
379 -- any attempt to enable \fBedonr\fR on a root pool will fail with an
380 error.
381
382 .SH "SEE ALSO"
383 \fBzpool\fR(1M)
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