In the Maronite Church, following our synod that was essentially an adaptation of Trent, we eliminated the deaconate - prior to this this was not the case. Deacons play an integral role in Eastern liturgy, Eastern and Oriental alike, and so we even have 4 ranks of deacon (cantor, lector, subdeacon, “full” deacon). From my experience in the Syriac Churches, their primary concern seems to be the chanting of responses and serving the priest at the altar (i.e. fanning rapidia, etc.).
Actually the so-called “permanent” diaconte (and subdiaconate) wasn’t exactly eliminated by the Black Council (which was very hotly contested for quite some years). It’s more like it faded away starting then. The same is essentially true of the Minor Orders of Cantor and Lector as well. Deacons, along with subdeacons, were often village elders. There were, apparently, some few of both up until the early 20th Century (pre-WWI).
Yes it also was true in the eastern Catholic churches, yet it was still possible to be ordained.Robert Clément, S.J. writing in 1966 shortly after the promulgation of Orientalium ecclesiarum addresses the situation of the diaconate in both the Orthodox and Eastern Catholic Churches. (Cf. “Situation Présente du Diaconate en Orient” in P Winninger et Y. Congar. Le Diacre Dans L’Eglise et Le Monde D’aujourd’hui. Paris: Les Éditions du Cerf. 1966. 63-70.) He states that among the Chaldean Catholics there are 5 deacons and 3 for the Syrians. He mentions that among the Maronites deacons can be found in the monasteries but he gives no numbers. He mentions that in the Orthodox Church in Russia in 1914 there were 15,210 deacons, 50,150 presbyters and 149 bishops for 100 million faithful in 67 dioceses. Yet in the Orthodox Church in Greece, Clément tells us that it is rare to find deacons who will serve permanently in that order. There, deacons are awaiting ordination to the presbyterate or are found on the staff of bishops where they frequently go on to the episcopate itself; sometimes only a day or two after presbyteral ordination. We can easily see that among the Eastern Catholics and among some of the Orthodox that the diaconate as a permanent order “had fallen into disuse”.